case study potential problems

  • Discussion Forum
  • Top Challenges for Case Study Programs

What gets in the way of case study adoption? The Case Studies Affinity Group, a consortium of Harvard-affiliated case programs, took up this question during its quarterly meeting on May 12. The Affinity Group welcomed as panelists Carolyn Wood, Assistant Academic Dean & Director of SLATE and the Case Program, Harvard Kennedy School; Lisa Rohrer, Executive Director of the Case Development Initiative at Harvard Law School; and Susan Madden, Associate Director, Case-Based Teaching and Learning Center, Harvard T.H. Chan School of Public Health. Together, the panelists identified key challenges facing case study programs at Harvard and beyond:

  • Poor visibility. A searchable index of all available case materials is a fundamental resource, but surprisingly challenging to achieve when instructors write case studies for their own courses. This index must be featured prominently in faculty onboarding or resource pages; ideally, faculty would receive formal pedagogical training or advising on available curricular resources. According to Wood, the Kennedy School of Government circulates an e-update three times per year to 80+ HKS faculty to highlight new cases and share high-level statistics and FAQs on case teaching and case usage. HKS also reaches out to instructors directly, suggesting a few new case studies specifically tailored to their course(s).
  • Few role models and mentors. The prevalence of poorly-facilitated case discussions can undermine support for case method teaching, but a skilled, energizing case teacher can transform student learning and inspire fellow faculty. Case study programs need respected opinion leaders on the faculty to act as champions; if such role models also direct or supervise case programs, the programs themselves can develop from this galvanizing leadership.
  • Incentive structure. Faculty members are typically promoted based primarily on research and scholarship, while teaching is thought to be weighted less. We need career incentives for faculty to stay on the cutting edge of pedagogy. In the interim, we can make the case development effort worthwhile for faculty by dovetailing case topics with faculty research interests, so that there is a greater return on investment for case research.
  • Lack of testing environments. Instructors need spaces to test new teaching styles outside of the classroom. Workshops where instructors test-teach short cases and see peer approaches would increase success, confidence, and ease for new case teachers.
  • The challenge of case teaching. Case teaching has been the dominant means of instruction in business schools across the globe for decades.  It can seem intimidating for instructors in fields outside of business to adopt case method teaching when they lack a stock of tested cases in their field, robust training, and the pervasive culture of case teaching that is so prevalent in business schools. Public policy faculty often practice case teaching in a more heterogeneous manner than their business school colleagues. Wood muses, “Even the most skilled case teachers at HKS are often reluctant to call themselves case teachers, perhaps because they’re uncertain they meet the HBS definition of a true ‘case teacher.’ But in our context, there’s room for variation in how case method teaching is practiced so long as it’s done in a manner that advances active learning.  It’s all about using authentic problems to push students to practice higher-order thinking skills (analysis, decision-making, advocacy) in a group context in class.”  Susan Madden notes that Emory University addresses this barrierby hosting a global health case study competition , encouraging multidisciplinary teams.
  • Benefits of traditional materials . According to Wood, some HKS faculty report that students read less carefully in the digital age; it is hard for students to skim case studies and still contribute deeply to the discussion. Furthermore, in legal education casebooks and lectures provide a broad abundance of information; it is hard for instructors to cut a lot of material and replace it with one deep scenario. However, instructors have successfully paired traditional legal cases with case studies, so that students may extrapolate to other scenarios. To achieve breadth with a single case study, instructors can mine the text for lessons comparable to those in legal casebooks, and lead students to articulate enduring, transferable takeaways.

Nonetheless, case study adoption should be slow. Wood explains that it is better to have a small number of instructors who teach cases well than many who teach ineffectively. Relationships between case writers and faculty take time to build; quality cases take time to research and write. With a foundation of quality, case study programs can address their challenges without undercutting the main objective: more engaged, thoughtful teaching and learning.

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  • What Is a Case Study? | Definition, Examples & Methods

What Is a Case Study? | Definition, Examples & Methods

Published on May 8, 2019 by Shona McCombes . Revised on November 20, 2023.

A case study is a detailed study of a specific subject, such as a person, group, place, event, organization, or phenomenon. Case studies are commonly used in social, educational, clinical, and business research.

A case study research design usually involves qualitative methods , but quantitative methods are sometimes also used. Case studies are good for describing , comparing, evaluating and understanding different aspects of a research problem .

Table of contents

When to do a case study, step 1: select a case, step 2: build a theoretical framework, step 3: collect your data, step 4: describe and analyze the case, other interesting articles.

A case study is an appropriate research design when you want to gain concrete, contextual, in-depth knowledge about a specific real-world subject. It allows you to explore the key characteristics, meanings, and implications of the case.

Case studies are often a good choice in a thesis or dissertation . They keep your project focused and manageable when you don’t have the time or resources to do large-scale research.

You might use just one complex case study where you explore a single subject in depth, or conduct multiple case studies to compare and illuminate different aspects of your research problem.

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Once you have developed your problem statement and research questions , you should be ready to choose the specific case that you want to focus on. A good case study should have the potential to:

  • Provide new or unexpected insights into the subject
  • Challenge or complicate existing assumptions and theories
  • Propose practical courses of action to resolve a problem
  • Open up new directions for future research

TipIf your research is more practical in nature and aims to simultaneously investigate an issue as you solve it, consider conducting action research instead.

Unlike quantitative or experimental research , a strong case study does not require a random or representative sample. In fact, case studies often deliberately focus on unusual, neglected, or outlying cases which may shed new light on the research problem.

Example of an outlying case studyIn the 1960s the town of Roseto, Pennsylvania was discovered to have extremely low rates of heart disease compared to the US average. It became an important case study for understanding previously neglected causes of heart disease.

However, you can also choose a more common or representative case to exemplify a particular category, experience or phenomenon.

Example of a representative case studyIn the 1920s, two sociologists used Muncie, Indiana as a case study of a typical American city that supposedly exemplified the changing culture of the US at the time.

While case studies focus more on concrete details than general theories, they should usually have some connection with theory in the field. This way the case study is not just an isolated description, but is integrated into existing knowledge about the topic. It might aim to:

  • Exemplify a theory by showing how it explains the case under investigation
  • Expand on a theory by uncovering new concepts and ideas that need to be incorporated
  • Challenge a theory by exploring an outlier case that doesn’t fit with established assumptions

To ensure that your analysis of the case has a solid academic grounding, you should conduct a literature review of sources related to the topic and develop a theoretical framework . This means identifying key concepts and theories to guide your analysis and interpretation.

There are many different research methods you can use to collect data on your subject. Case studies tend to focus on qualitative data using methods such as interviews , observations , and analysis of primary and secondary sources (e.g., newspaper articles, photographs, official records). Sometimes a case study will also collect quantitative data.

Example of a mixed methods case studyFor a case study of a wind farm development in a rural area, you could collect quantitative data on employment rates and business revenue, collect qualitative data on local people’s perceptions and experiences, and analyze local and national media coverage of the development.

The aim is to gain as thorough an understanding as possible of the case and its context.

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case study potential problems

In writing up the case study, you need to bring together all the relevant aspects to give as complete a picture as possible of the subject.

How you report your findings depends on the type of research you are doing. Some case studies are structured like a standard scientific paper or thesis , with separate sections or chapters for the methods , results and discussion .

Others are written in a more narrative style, aiming to explore the case from various angles and analyze its meanings and implications (for example, by using textual analysis or discourse analysis ).

In all cases, though, make sure to give contextual details about the case, connect it back to the literature and theory, and discuss how it fits into wider patterns or debates.

If you want to know more about statistics , methodology , or research bias , make sure to check out some of our other articles with explanations and examples.

  • Normal distribution
  • Degrees of freedom
  • Null hypothesis
  • Discourse analysis
  • Control groups
  • Mixed methods research
  • Non-probability sampling
  • Quantitative research
  • Ecological validity

Research bias

  • Rosenthal effect
  • Implicit bias
  • Cognitive bias
  • Selection bias
  • Negativity bias
  • Status quo bias

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Do Your Students Know How to Analyze a Case—Really?

Explore more.

  • Case Teaching
  • Student Engagement

J ust as actors, athletes, and musicians spend thousands of hours practicing their craft, business students benefit from practicing their critical-thinking and decision-making skills. Students, however, often have limited exposure to real-world problem-solving scenarios; they need more opportunities to practice tackling tough business problems and deciding on—and executing—the best solutions.

To ensure students have ample opportunity to develop these critical-thinking and decision-making skills, we believe business faculty should shift from teaching mostly principles and ideas to mostly applications and practices. And in doing so, they should emphasize the case method, which simulates real-world management challenges and opportunities for students.

To help educators facilitate this shift and help students get the most out of case-based learning, we have developed a framework for analyzing cases. We call it PACADI (Problem, Alternatives, Criteria, Analysis, Decision, Implementation); it can improve learning outcomes by helping students better solve and analyze business problems, make decisions, and develop and implement strategy. Here, we’ll explain why we developed this framework, how it works, and what makes it an effective learning tool.

The Case for Cases: Helping Students Think Critically

Business students must develop critical-thinking and analytical skills, which are essential to their ability to make good decisions in functional areas such as marketing, finance, operations, and information technology, as well as to understand the relationships among these functions. For example, the decisions a marketing manager must make include strategic planning (segments, products, and channels); execution (digital messaging, media, branding, budgets, and pricing); and operations (integrated communications and technologies), as well as how to implement decisions across functional areas.

Faculty can use many types of cases to help students develop these skills. These include the prototypical “paper cases”; live cases , which feature guest lecturers such as entrepreneurs or corporate leaders and on-site visits; and multimedia cases , which immerse students into real situations. Most cases feature an explicit or implicit decision that a protagonist—whether it is an individual, a group, or an organization—must make.

For students new to learning by the case method—and even for those with case experience—some common issues can emerge; these issues can sometimes be a barrier for educators looking to ensure the best possible outcomes in their case classrooms. Unsure of how to dig into case analysis on their own, students may turn to the internet or rely on former students for “answers” to assigned cases. Or, when assigned to provide answers to assignment questions in teams, students might take a divide-and-conquer approach but not take the time to regroup and provide answers that are consistent with one other.

To help address these issues, which we commonly experienced in our classes, we wanted to provide our students with a more structured approach for how they analyze cases—and to really think about making decisions from the protagonists’ point of view. We developed the PACADI framework to address this need.

PACADI: A Six-Step Decision-Making Approach

The PACADI framework is a six-step decision-making approach that can be used in lieu of traditional end-of-case questions. It offers a structured, integrated, and iterative process that requires students to analyze case information, apply business concepts to derive valuable insights, and develop recommendations based on these insights.

Prior to beginning a PACADI assessment, which we’ll outline here, students should first prepare a two-paragraph summary—a situation analysis—that highlights the key case facts. Then, we task students with providing a five-page PACADI case analysis (excluding appendices) based on the following six steps.

Step 1: Problem definition. What is the major challenge, problem, opportunity, or decision that has to be made? If there is more than one problem, choose the most important one. Often when solving the key problem, other issues will surface and be addressed. The problem statement may be framed as a question; for example, How can brand X improve market share among millennials in Canada? Usually the problem statement has to be re-written several times during the analysis of a case as students peel back the layers of symptoms or causation.

Step 2: Alternatives. Identify in detail the strategic alternatives to address the problem; three to five options generally work best. Alternatives should be mutually exclusive, realistic, creative, and feasible given the constraints of the situation. Doing nothing or delaying the decision to a later date are not considered acceptable alternatives.

Step 3: Criteria. What are the key decision criteria that will guide decision-making? In a marketing course, for example, these may include relevant marketing criteria such as segmentation, positioning, advertising and sales, distribution, and pricing. Financial criteria useful in evaluating the alternatives should be included—for example, income statement variables, customer lifetime value, payback, etc. Students must discuss their rationale for selecting the decision criteria and the weights and importance for each factor.

Step 4: Analysis. Provide an in-depth analysis of each alternative based on the criteria chosen in step three. Decision tables using criteria as columns and alternatives as rows can be helpful. The pros and cons of the various choices as well as the short- and long-term implications of each may be evaluated. Best, worst, and most likely scenarios can also be insightful.

Step 5: Decision. Students propose their solution to the problem. This decision is justified based on an in-depth analysis. Explain why the recommendation made is the best fit for the criteria.

Step 6: Implementation plan. Sound business decisions may fail due to poor execution. To enhance the likeliness of a successful project outcome, students describe the key steps (activities) to implement the recommendation, timetable, projected costs, expected competitive reaction, success metrics, and risks in the plan.

“Students note that using the PACADI framework yields ‘aha moments’—they learned something surprising in the case that led them to think differently about the problem and their proposed solution.”

PACADI’s Benefits: Meaningfully and Thoughtfully Applying Business Concepts

The PACADI framework covers all of the major elements of business decision-making, including implementation, which is often overlooked. By stepping through the whole framework, students apply relevant business concepts and solve management problems via a systematic, comprehensive approach; they’re far less likely to surface piecemeal responses.

As students explore each part of the framework, they may realize that they need to make changes to a previous step. For instance, when working on implementation, students may realize that the alternative they selected cannot be executed or will not be profitable, and thus need to rethink their decision. Or, they may discover that the criteria need to be revised since the list of decision factors they identified is incomplete (for example, the factors may explain key marketing concerns but fail to address relevant financial considerations) or is unrealistic (for example, they suggest a 25 percent increase in revenues without proposing an increased promotional budget).

In addition, the PACADI framework can be used alongside quantitative assignments, in-class exercises, and business and management simulations. The structured, multi-step decision framework encourages careful and sequential analysis to solve business problems. Incorporating PACADI as an overarching decision-making method across different projects will ultimately help students achieve desired learning outcomes. As a practical “beyond-the-classroom” tool, the PACADI framework is not a contrived course assignment; it reflects the decision-making approach that managers, executives, and entrepreneurs exercise daily. Case analysis introduces students to the real-world process of making business decisions quickly and correctly, often with limited information. This framework supplies an organized and disciplined process that students can readily defend in writing and in class discussions.

PACADI in Action: An Example

Here’s an example of how students used the PACADI framework for a recent case analysis on CVS, a large North American drugstore chain.

The CVS Prescription for Customer Value*

PACADI Stage

Summary Response

How should CVS Health evolve from the “drugstore of your neighborhood” to the “drugstore of your future”?

Alternatives

A1. Kaizen (continuous improvement)

A2. Product development

A3. Market development

A4. Personalization (micro-targeting)

Criteria (include weights)

C1. Customer value: service, quality, image, and price (40%)

C2. Customer obsession (20%)

C3. Growth through related businesses (20%)

C4. Customer retention and customer lifetime value (20%)

Each alternative was analyzed by each criterion using a Customer Value Assessment Tool

Alternative 4 (A4): Personalization was selected. This is operationalized via: segmentation—move toward segment-of-1 marketing; geodemographics and lifestyle emphasis; predictive data analysis; relationship marketing; people, principles, and supply chain management; and exceptional customer service.

Implementation

Partner with leading medical school

Curbside pick-up

Pet pharmacy

E-newsletter for customers and employees

Employee incentive program

CVS beauty days

Expand to Latin America and Caribbean

Healthier/happier corner

Holiday toy drives/community outreach

*Source: A. Weinstein, Y. Rodriguez, K. Sims, R. Vergara, “The CVS Prescription for Superior Customer Value—A Case Study,” Back to the Future: Revisiting the Foundations of Marketing from Society for Marketing Advances, West Palm Beach, FL (November 2, 2018).

Results of Using the PACADI Framework

When faculty members at our respective institutions at Nova Southeastern University (NSU) and the University of North Carolina Wilmington have used the PACADI framework, our classes have been more structured and engaging. Students vigorously debate each element of their decision and note that this framework yields an “aha moment”—they learned something surprising in the case that led them to think differently about the problem and their proposed solution.

These lively discussions enhance individual and collective learning. As one external metric of this improvement, we have observed a 2.5 percent increase in student case grade performance at NSU since this framework was introduced.

Tips to Get Started

The PACADI approach works well in in-person, online, and hybrid courses. This is particularly important as more universities have moved to remote learning options. Because students have varied educational and cultural backgrounds, work experience, and familiarity with case analysis, we recommend that faculty members have students work on their first case using this new framework in small teams (two or three students). Additional analyses should then be solo efforts.

To use PACADI effectively in your classroom, we suggest the following:

Advise your students that your course will stress critical thinking and decision-making skills, not just course concepts and theory.

Use a varied mix of case studies. As marketing professors, we often address consumer and business markets; goods, services, and digital commerce; domestic and global business; and small and large companies in a single MBA course.

As a starting point, provide a short explanation (about 20 to 30 minutes) of the PACADI framework with a focus on the conceptual elements. You can deliver this face to face or through videoconferencing.

Give students an opportunity to practice the case analysis methodology via an ungraded sample case study. Designate groups of five to seven students to discuss the case and the six steps in breakout sessions (in class or via Zoom).

Ensure case analyses are weighted heavily as a grading component. We suggest 30–50 percent of the overall course grade.

Once cases are graded, debrief with the class on what they did right and areas needing improvement (30- to 40-minute in-person or Zoom session).

Encourage faculty teams that teach common courses to build appropriate instructional materials, grading rubrics, videos, sample cases, and teaching notes.

When selecting case studies, we have found that the best ones for PACADI analyses are about 15 pages long and revolve around a focal management decision. This length provides adequate depth yet is not protracted. Some of our tested and favorite marketing cases include Brand W , Hubspot , Kraft Foods Canada , TRSB(A) , and Whiskey & Cheddar .

Art Weinstein

Art Weinstein , Ph.D., is a professor of marketing at Nova Southeastern University, Fort Lauderdale, Florida. He has published more than 80 scholarly articles and papers and eight books on customer-focused marketing strategy. His latest book is Superior Customer Value—Finding and Keeping Customers in the Now Economy . Dr. Weinstein has consulted for many leading technology and service companies.

Herbert V. Brotspies

Herbert V. Brotspies , D.B.A., is an adjunct professor of marketing at Nova Southeastern University. He has over 30 years’ experience as a vice president in marketing, strategic planning, and acquisitions for Fortune 50 consumer products companies working in the United States and internationally. His research interests include return on marketing investment, consumer behavior, business-to-business strategy, and strategic planning.

John T. Gironda

John T. Gironda , Ph.D., is an assistant professor of marketing at the University of North Carolina Wilmington. His research has been published in Industrial Marketing Management, Psychology & Marketing , and Journal of Marketing Management . He has also presented at major marketing conferences including the American Marketing Association, Academy of Marketing Science, and Society for Marketing Advances.

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What the Case Study Method Really Teaches

  • Nitin Nohria

case study potential problems

Seven meta-skills that stick even if the cases fade from memory.

It’s been 100 years since Harvard Business School began using the case study method. Beyond teaching specific subject matter, the case study method excels in instilling meta-skills in students. This article explains the importance of seven such skills: preparation, discernment, bias recognition, judgement, collaboration, curiosity, and self-confidence.

During my decade as dean of Harvard Business School, I spent hundreds of hours talking with our alumni. To enliven these conversations, I relied on a favorite question: “What was the most important thing you learned from your time in our MBA program?”

  • Nitin Nohria is the George F. Baker Jr. Professor at Harvard Business School and the former dean of HBS.

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  • Open access
  • Published: 10 November 2020

Case study research for better evaluations of complex interventions: rationale and challenges

  • Sara Paparini   ORCID: orcid.org/0000-0002-1909-2481 1 ,
  • Judith Green 2 ,
  • Chrysanthi Papoutsi 1 ,
  • Jamie Murdoch 3 ,
  • Mark Petticrew 4 ,
  • Trish Greenhalgh 1 ,
  • Benjamin Hanckel 5 &
  • Sara Shaw 1  

BMC Medicine volume  18 , Article number:  301 ( 2020 ) Cite this article

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The need for better methods for evaluation in health research has been widely recognised. The ‘complexity turn’ has drawn attention to the limitations of relying on causal inference from randomised controlled trials alone for understanding whether, and under which conditions, interventions in complex systems improve health services or the public health, and what mechanisms might link interventions and outcomes. We argue that case study research—currently denigrated as poor evidence—is an under-utilised resource for not only providing evidence about context and transferability, but also for helping strengthen causal inferences when pathways between intervention and effects are likely to be non-linear.

Case study research, as an overall approach, is based on in-depth explorations of complex phenomena in their natural, or real-life, settings. Empirical case studies typically enable dynamic understanding of complex challenges and provide evidence about causal mechanisms and the necessary and sufficient conditions (contexts) for intervention implementation and effects. This is essential evidence not just for researchers concerned about internal and external validity, but also research users in policy and practice who need to know what the likely effects of complex programmes or interventions will be in their settings. The health sciences have much to learn from scholarship on case study methodology in the social sciences. However, there are multiple challenges in fully exploiting the potential learning from case study research. First are misconceptions that case study research can only provide exploratory or descriptive evidence. Second, there is little consensus about what a case study is, and considerable diversity in how empirical case studies are conducted and reported. Finally, as case study researchers typically (and appropriately) focus on thick description (that captures contextual detail), it can be challenging to identify the key messages related to intervention evaluation from case study reports.

Whilst the diversity of published case studies in health services and public health research is rich and productive, we recommend further clarity and specific methodological guidance for those reporting case study research for evaluation audiences.

Peer Review reports

The need for methodological development to address the most urgent challenges in health research has been well-documented. Many of the most pressing questions for public health research, where the focus is on system-level determinants [ 1 , 2 ], and for health services research, where provisions typically vary across sites and are provided through interlocking networks of services [ 3 ], require methodological approaches that can attend to complexity. The need for methodological advance has arisen, in part, as a result of the diminishing returns from randomised controlled trials (RCTs) where they have been used to answer questions about the effects of interventions in complex systems [ 4 , 5 , 6 ]. In conditions of complexity, there is limited value in maintaining the current orientation to experimental trial designs in the health sciences as providing ‘gold standard’ evidence of effect.

There are increasing calls for methodological pluralism [ 7 , 8 ], with the recognition that complex intervention and context are not easily or usefully separated (as is often the situation when using trial design), and that system interruptions may have effects that are not reducible to linear causal pathways between intervention and outcome. These calls are reflected in a shifting and contested discourse of trial design, seen with the emergence of realist [ 9 ], adaptive and hybrid (types 1, 2 and 3) [ 10 , 11 ] trials that blend studies of effectiveness with a close consideration of the contexts of implementation. Similarly, process evaluation has now become a core component of complex healthcare intervention trials, reflected in MRC guidance on how to explore implementation, causal mechanisms and context [ 12 ].

Evidence about the context of an intervention is crucial for questions of external validity. As Woolcock [ 4 ] notes, even if RCT designs are accepted as robust for maximising internal validity, questions of transferability (how well the intervention works in different contexts) and generalisability (how well the intervention can be scaled up) remain unanswered [ 5 , 13 ]. For research evidence to have impact on policy and systems organisation, and thus to improve population and patient health, there is an urgent need for better methods for strengthening external validity, including a better understanding of the relationship between intervention and context [ 14 ].

Policymakers, healthcare commissioners and other research users require credible evidence of relevance to their settings and populations [ 15 ], to perform what Rosengarten and Savransky [ 16 ] call ‘careful abstraction’ to the locales that matter for them. They also require robust evidence for understanding complex causal pathways. Case study research, currently under-utilised in public health and health services evaluation, can offer considerable potential for strengthening faith in both external and internal validity. For example, in an empirical case study of how the policy of free bus travel had specific health effects in London, UK, a quasi-experimental evaluation (led by JG) identified how important aspects of context (a good public transport system) and intervention (that it was universal) were necessary conditions for the observed effects, thus providing useful, actionable evidence for decision-makers in other contexts [ 17 ].

The overall approach of case study research is based on the in-depth exploration of complex phenomena in their natural, or ‘real-life’, settings. Empirical case studies typically enable dynamic understanding of complex challenges rather than restricting the focus on narrow problem delineations and simple fixes. Case study research is a diverse and somewhat contested field, with multiple definitions and perspectives grounded in different ways of viewing the world, and involving different combinations of methods. In this paper, we raise awareness of such plurality and highlight the contribution that case study research can make to the evaluation of complex system-level interventions. We review some of the challenges in exploiting the current evidence base from empirical case studies and conclude by recommending that further guidance and minimum reporting criteria for evaluation using case studies, appropriate for audiences in the health sciences, can enhance the take-up of evidence from case study research.

Case study research offers evidence about context, causal inference in complex systems and implementation

Well-conducted and described empirical case studies provide evidence on context, complexity and mechanisms for understanding how, where and why interventions have their observed effects. Recognition of the importance of context for understanding the relationships between interventions and outcomes is hardly new. In 1943, Canguilhem berated an over-reliance on experimental designs for determining universal physiological laws: ‘As if one could determine a phenomenon’s essence apart from its conditions! As if conditions were a mask or frame which changed neither the face nor the picture!’ ([ 18 ] p126). More recently, a concern with context has been expressed in health systems and public health research as part of what has been called the ‘complexity turn’ [ 1 ]: a recognition that many of the most enduring challenges for developing an evidence base require a consideration of system-level effects [ 1 ] and the conceptualisation of interventions as interruptions in systems [ 19 ].

The case study approach is widely recognised as offering an invaluable resource for understanding the dynamic and evolving influence of context on complex, system-level interventions [ 20 , 21 , 22 , 23 ]. Empirically, case studies can directly inform assessments of where, when, how and for whom interventions might be successfully implemented, by helping to specify the necessary and sufficient conditions under which interventions might have effects and to consolidate learning on how interdependencies, emergence and unpredictability can be managed to achieve and sustain desired effects. Case study research has the potential to address four objectives for improving research and reporting of context recently set out by guidance on taking account of context in population health research [ 24 ], that is to (1) improve the appropriateness of intervention development for specific contexts, (2) improve understanding of ‘how’ interventions work, (3) better understand how and why impacts vary across contexts and (4) ensure reports of intervention studies are most useful for decision-makers and researchers.

However, evaluations of complex healthcare interventions have arguably not exploited the full potential of case study research and can learn much from other disciplines. For evaluative research, exploratory case studies have had a traditional role of providing data on ‘process’, or initial ‘hypothesis-generating’ scoping, but might also have an increasing salience for explanatory aims. Across the social and political sciences, different kinds of case studies are undertaken to meet diverse aims (description, exploration or explanation) and across different scales (from small N qualitative studies that aim to elucidate processes, or provide thick description, to more systematic techniques designed for medium-to-large N cases).

Case studies with explanatory aims vary in terms of their positioning within mixed-methods projects, with designs including (but not restricted to) (1) single N of 1 studies of interventions in specific contexts, where the overall design is a case study that may incorporate one or more (randomised or not) comparisons over time and between variables within the case; (2) a series of cases conducted or synthesised to provide explanation from variations between cases; and (3) case studies of particular settings within RCT or quasi-experimental designs to explore variation in effects or implementation.

Detailed qualitative research (typically done as ‘case studies’ within process evaluations) provides evidence for the plausibility of mechanisms [ 25 ], offering theoretical generalisations for how interventions may function under different conditions. Although RCT designs reduce many threats to internal validity, the mechanisms of effect remain opaque, particularly when the causal pathways between ‘intervention’ and ‘effect’ are long and potentially non-linear: case study research has a more fundamental role here, in providing detailed observational evidence for causal claims [ 26 ] as well as producing a rich, nuanced picture of tensions and multiple perspectives [ 8 ].

Longitudinal or cross-case analysis may be best suited for evidence generation in system-level evaluative research. Turner [ 27 ], for instance, reflecting on the complex processes in major system change, has argued for the need for methods that integrate learning across cases, to develop theoretical knowledge that would enable inferences beyond the single case, and to develop generalisable theory about organisational and structural change in health systems. Qualitative Comparative Analysis (QCA) [ 28 ] is one such formal method for deriving causal claims, using set theory mathematics to integrate data from empirical case studies to answer questions about the configurations of causal pathways linking conditions to outcomes [ 29 , 30 ].

Nonetheless, the single N case study, too, provides opportunities for theoretical development [ 31 ], and theoretical generalisation or analytical refinement [ 32 ]. How ‘the case’ and ‘context’ are conceptualised is crucial here. Findings from the single case may seem to be confined to its intrinsic particularities in a specific and distinct context [ 33 ]. However, if such context is viewed as exemplifying wider social and political forces, the single case can be ‘telling’, rather than ‘typical’, and offer insight into a wider issue [ 34 ]. Internal comparisons within the case can offer rich possibilities for logical inferences about causation [ 17 ]. Further, case studies of any size can be used for theory testing through refutation [ 22 ]. The potential lies, then, in utilising the strengths and plurality of case study to support theory-driven research within different methodological paradigms.

Evaluation research in health has much to learn from a range of social sciences where case study methodology has been used to develop various kinds of causal inference. For instance, Gerring [ 35 ] expands on the within-case variations utilised to make causal claims. For Gerring [ 35 ], case studies come into their own with regard to invariant or strong causal claims (such as X is a necessary and/or sufficient condition for Y) rather than for probabilistic causal claims. For the latter (where experimental methods might have an advantage in estimating effect sizes), case studies offer evidence on mechanisms: from observations of X affecting Y, from process tracing or from pattern matching. Case studies also support the study of emergent causation, that is, the multiple interacting properties that account for particular and unexpected outcomes in complex systems, such as in healthcare [ 8 ].

Finally, efficacy (or beliefs about efficacy) is not the only contributor to intervention uptake, with a range of organisational and policy contingencies affecting whether an intervention is likely to be rolled out in practice. Case study research is, therefore, invaluable for learning about contextual contingencies and identifying the conditions necessary for interventions to become normalised (i.e. implemented routinely) in practice [ 36 ].

The challenges in exploiting evidence from case study research

At present, there are significant challenges in exploiting the benefits of case study research in evaluative health research, which relate to status, definition and reporting. Case study research has been marginalised at the bottom of an evidence hierarchy, seen to offer little by way of explanatory power, if nonetheless useful for adding descriptive data on process or providing useful illustrations for policymakers [ 37 ]. This is an opportune moment to revisit this low status. As health researchers are increasingly charged with evaluating ‘natural experiments’—the use of face masks in the response to the COVID-19 pandemic being a recent example [ 38 ]—rather than interventions that take place in settings that can be controlled, research approaches using methods to strengthen causal inference that does not require randomisation become more relevant.

A second challenge for improving the use of case study evidence in evaluative health research is that, as we have seen, what is meant by ‘case study’ varies widely, not only across but also within disciplines. There is indeed little consensus amongst methodologists as to how to define ‘a case study’. Definitions focus, variously, on small sample size or lack of control over the intervention (e.g. [ 39 ] p194), on in-depth study and context [ 40 , 41 ], on the logic of inference used [ 35 ] or on distinct research strategies which incorporate a number of methods to address questions of ‘how’ and ‘why’ [ 42 ]. Moreover, definitions developed for specific disciplines do not capture the range of ways in which case study research is carried out across disciplines. Multiple definitions of case study reflect the richness and diversity of the approach. However, evidence suggests that a lack of consensus across methodologists results in some of the limitations of published reports of empirical case studies [ 43 , 44 ]. Hyett and colleagues [ 43 ], for instance, reviewing reports in qualitative journals, found little match between methodological definitions of case study research and how authors used the term.

This raises the third challenge we identify that case study reports are typically not written in ways that are accessible or useful for the evaluation research community and policymakers. Case studies may not appear in journals widely read by those in the health sciences, either because space constraints preclude the reporting of rich, thick descriptions, or because of the reported lack of willingness of some biomedical journals to publish research that uses qualitative methods [ 45 ], signalling the persistence of the aforementioned evidence hierarchy. Where they do, however, the term ‘case study’ is used to indicate, interchangeably, a qualitative study, an N of 1 sample, or a multi-method, in-depth analysis of one example from a population of phenomena. Definitions of what constitutes the ‘case’ are frequently lacking and appear to be used as a synonym for the settings in which the research is conducted. Despite offering insights for evaluation, the primary aims may not have been evaluative, so the implications may not be explicitly drawn out. Indeed, some case study reports might properly be aiming for thick description without necessarily seeking to inform about context or causality.

Acknowledging plurality and developing guidance

We recognise that definitional and methodological plurality is not only inevitable, but also a necessary and creative reflection of the very different epistemological and disciplinary origins of health researchers, and the aims they have in doing and reporting case study research. Indeed, to provide some clarity, Thomas [ 46 ] has suggested a typology of subject/purpose/approach/process for classifying aims (e.g. evaluative or exploratory), sample rationale and selection and methods for data generation of case studies. We also recognise that the diversity of methods used in case study research, and the necessary focus on narrative reporting, does not lend itself to straightforward development of formal quality or reporting criteria.

Existing checklists for reporting case study research from the social sciences—for example Lincoln and Guba’s [ 47 ] and Stake’s [ 33 ]—are primarily orientated to the quality of narrative produced, and the extent to which they encapsulate thick description, rather than the more pragmatic issues of implications for intervention effects. Those designed for clinical settings, such as the CARE (CAse REports) guidelines, provide specific reporting guidelines for medical case reports about single, or small groups of patients [ 48 ], not for case study research.

The Design of Case Study Research in Health Care (DESCARTE) model [ 44 ] suggests a series of questions to be asked of a case study researcher (including clarity about the philosophy underpinning their research), study design (with a focus on case definition) and analysis (to improve process). The model resembles toolkits for enhancing the quality and robustness of qualitative and mixed-methods research reporting, and it is usefully open-ended and non-prescriptive. However, even if it does include some reflections on context, the model does not fully address aspects of context, logic and causal inference that are perhaps most relevant for evaluative research in health.

Hence, for evaluative research where the aim is to report empirical findings in ways that are intended to be pragmatically useful for health policy and practice, this may be an opportune time to consider how to best navigate plurality around what is (minimally) important to report when publishing empirical case studies, especially with regards to the complex relationships between context and interventions, information that case study research is well placed to provide.

The conventional scientific quest for certainty, predictability and linear causality (maximised in RCT designs) has to be augmented by the study of uncertainty, unpredictability and emergent causality [ 8 ] in complex systems. This will require methodological pluralism, and openness to broadening the evidence base to better understand both causality in and the transferability of system change intervention [ 14 , 20 , 23 , 25 ]. Case study research evidence is essential, yet is currently under exploited in the health sciences. If evaluative health research is to move beyond the current impasse on methods for understanding interventions as interruptions in complex systems, we need to consider in more detail how researchers can conduct and report empirical case studies which do aim to elucidate the contextual factors which interact with interventions to produce particular effects. To this end, supported by the UK’s Medical Research Council, we are embracing the challenge to develop guidance for case study researchers studying complex interventions. Following a meta-narrative review of the literature, we are planning a Delphi study to inform guidance that will, at minimum, cover the value of case study research for evaluating the interrelationship between context and complex system-level interventions; for situating and defining ‘the case’, and generalising from case studies; as well as provide specific guidance on conducting, analysing and reporting case study research. Our hope is that such guidance can support researchers evaluating interventions in complex systems to better exploit the diversity and richness of case study research.

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Abbreviations

Qualitative comparative analysis

Quasi-experimental design

Randomised controlled trial

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This work was funded by the Medical Research Council - MRC Award MR/S014632/1 HCS: Case study, Context and Complex interventions (TRIPLE C). SP was additionally funded by the University of Oxford's Higher Education Innovation Fund (HEIF).

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Paparini, S., Green, J., Papoutsi, C. et al. Case study research for better evaluations of complex interventions: rationale and challenges. BMC Med 18 , 301 (2020). https://doi.org/10.1186/s12916-020-01777-6

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Many who would like to improve patient safety in health care have advocated for the widespread adoption of computerized physician order entry and electronic medical records. However, unforeseen consequences of this new technology may put patients at greater risk of harm, not less. The authors present a clinical scenario that demonstrates system vulnerabilities in the interface between humans and such technology. Furthermore, the authors suggest that managers could anticipate these vulnerabilities by using techniques such as cause-and-effect analysis or failure mode and effect analysis, both before the installation of electronic medical records and as ongoing surveillance mechanisms. The case study demonstrates that adoption of technology is not a quick fix to the patient safety issue; proactive and ongoing efforts to address the human factors issues raised by the introduction of new technology will be required to prevent patient harm.

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5 Benefits of Learning Through the Case Study Method

Harvard Business School MBA students learning through the case study method

  • 28 Nov 2023

While several factors make HBS Online unique —including a global Community and real-world outcomes —active learning through the case study method rises to the top.

In a 2023 City Square Associates survey, 74 percent of HBS Online learners who also took a course from another provider said HBS Online’s case method and real-world examples were better by comparison.

Here’s a primer on the case method, five benefits you could gain, and how to experience it for yourself.

Access your free e-book today.

What Is the Harvard Business School Case Study Method?

The case study method , or case method , is a learning technique in which you’re presented with a real-world business challenge and asked how you’d solve it. After working through it yourself and with peers, you’re told how the scenario played out.

HBS pioneered the case method in 1922. Shortly before, in 1921, the first case was written.

“How do you go into an ambiguous situation and get to the bottom of it?” says HBS Professor Jan Rivkin, former senior associate dean and chair of HBS's master of business administration (MBA) program, in a video about the case method . “That skill—the skill of figuring out a course of inquiry to choose a course of action—that skill is as relevant today as it was in 1921.”

Originally developed for the in-person MBA classroom, HBS Online adapted the case method into an engaging, interactive online learning experience in 2014.

In HBS Online courses , you learn about each case from the business professional who experienced it. After reviewing their videos, you’re prompted to take their perspective and explain how you’d handle their situation.

You then get to read peers’ responses, “star” them, and comment to further the discussion. Afterward, you learn how the professional handled it and their key takeaways.

HBS Online’s adaptation of the case method incorporates the famed HBS “cold call,” in which you’re called on at random to make a decision without time to prepare.

“Learning came to life!” said Sheneka Balogun , chief administration officer and chief of staff at LeMoyne-Owen College, of her experience taking the Credential of Readiness (CORe) program . “The videos from the professors, the interactive cold calls where you were randomly selected to participate, and the case studies that enhanced and often captured the essence of objectives and learning goals were all embedded in each module. This made learning fun, engaging, and student-friendly.”

If you’re considering taking a course that leverages the case study method, here are five benefits you could experience.

5 Benefits of Learning Through Case Studies

1. take new perspectives.

The case method prompts you to consider a scenario from another person’s perspective. To work through the situation and come up with a solution, you must consider their circumstances, limitations, risk tolerance, stakeholders, resources, and potential consequences to assess how to respond.

Taking on new perspectives not only can help you navigate your own challenges but also others’. Putting yourself in someone else’s situation to understand their motivations and needs can go a long way when collaborating with stakeholders.

2. Hone Your Decision-Making Skills

Another skill you can build is the ability to make decisions effectively . The case study method forces you to use limited information to decide how to handle a problem—just like in the real world.

Throughout your career, you’ll need to make difficult decisions with incomplete or imperfect information—and sometimes, you won’t feel qualified to do so. Learning through the case method allows you to practice this skill in a low-stakes environment. When facing a real challenge, you’ll be better prepared to think quickly, collaborate with others, and present and defend your solution.

3. Become More Open-Minded

As you collaborate with peers on responses, it becomes clear that not everyone solves problems the same way. Exposing yourself to various approaches and perspectives can help you become a more open-minded professional.

When you’re part of a diverse group of learners from around the world, your experiences, cultures, and backgrounds contribute to a range of opinions on each case.

On the HBS Online course platform, you’re prompted to view and comment on others’ responses, and discussion is encouraged. This practice of considering others’ perspectives can make you more receptive in your career.

“You’d be surprised at how much you can learn from your peers,” said Ratnaditya Jonnalagadda , a software engineer who took CORe.

In addition to interacting with peers in the course platform, Jonnalagadda was part of the HBS Online Community , where he networked with other professionals and continued discussions sparked by course content.

“You get to understand your peers better, and students share examples of businesses implementing a concept from a module you just learned,” Jonnalagadda said. “It’s a very good way to cement the concepts in one's mind.”

4. Enhance Your Curiosity

One byproduct of taking on different perspectives is that it enables you to picture yourself in various roles, industries, and business functions.

“Each case offers an opportunity for students to see what resonates with them, what excites them, what bores them, which role they could imagine inhabiting in their careers,” says former HBS Dean Nitin Nohria in the Harvard Business Review . “Cases stimulate curiosity about the range of opportunities in the world and the many ways that students can make a difference as leaders.”

Through the case method, you can “try on” roles you may not have considered and feel more prepared to change or advance your career .

5. Build Your Self-Confidence

Finally, learning through the case study method can build your confidence. Each time you assume a business leader’s perspective, aim to solve a new challenge, and express and defend your opinions and decisions to peers, you prepare to do the same in your career.

According to a 2022 City Square Associates survey , 84 percent of HBS Online learners report feeling more confident making business decisions after taking a course.

“Self-confidence is difficult to teach or coach, but the case study method seems to instill it in people,” Nohria says in the Harvard Business Review . “There may well be other ways of learning these meta-skills, such as the repeated experience gained through practice or guidance from a gifted coach. However, under the direction of a masterful teacher, the case method can engage students and help them develop powerful meta-skills like no other form of teaching.”

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If the case method seems like a good fit for your learning style, experience it for yourself by taking an HBS Online course. Offerings span seven subject areas, including:

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No matter which course or credential program you choose, you’ll examine case studies from real business professionals, work through their challenges alongside peers, and gain valuable insights to apply to your career.

Are you interested in discovering how HBS Online can help advance your career? Explore our course catalog and download our free guide —complete with interactive workbook sections—to determine if online learning is right for you and which course to take.

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  • Reviewing Collected Works
  • Writing a Case Analysis Paper
  • Writing a Case Study
  • About Informed Consent
  • Writing Field Notes
  • Writing a Policy Memo
  • Writing a Reflective Paper
  • Writing a Research Proposal
  • Generative AI and Writing
  • Acknowledgments

Definition and Introduction

Case analysis is a problem-based teaching and learning method that involves critically analyzing complex scenarios within an organizational setting for the purpose of placing the student in a “real world” situation and applying reflection and critical thinking skills to contemplate appropriate solutions, decisions, or recommended courses of action. It is considered a more effective teaching technique than in-class role playing or simulation activities. The analytical process is often guided by questions provided by the instructor that ask students to contemplate relationships between the facts and critical incidents described in the case.

Cases generally include both descriptive and statistical elements and rely on students applying abductive reasoning to develop and argue for preferred or best outcomes [i.e., case scenarios rarely have a single correct or perfect answer based on the evidence provided]. Rather than emphasizing theories or concepts, case analysis assignments emphasize building a bridge of relevancy between abstract thinking and practical application and, by so doing, teaches the value of both within a specific area of professional practice.

Given this, the purpose of a case analysis paper is to present a structured and logically organized format for analyzing the case situation. It can be assigned to students individually or as a small group assignment and it may include an in-class presentation component. Case analysis is predominately taught in economics and business-related courses, but it is also a method of teaching and learning found in other applied social sciences disciplines, such as, social work, public relations, education, journalism, and public administration.

Ellet, William. The Case Study Handbook: A Student's Guide . Revised Edition. Boston, MA: Harvard Business School Publishing, 2018; Christoph Rasche and Achim Seisreiner. Guidelines for Business Case Analysis . University of Potsdam; Writing a Case Analysis . Writing Center, Baruch College; Volpe, Guglielmo. "Case Teaching in Economics: History, Practice and Evidence." Cogent Economics and Finance 3 (December 2015). doi:https://doi.org/10.1080/23322039.2015.1120977.

How to Approach Writing a Case Analysis Paper

The organization and structure of a case analysis paper can vary depending on the organizational setting, the situation, and how your professor wants you to approach the assignment. Nevertheless, preparing to write a case analysis paper involves several important steps. As Hawes notes, a case analysis assignment “...is useful in developing the ability to get to the heart of a problem, analyze it thoroughly, and to indicate the appropriate solution as well as how it should be implemented” [p.48]. This statement encapsulates how you should approach preparing to write a case analysis paper.

Before you begin to write your paper, consider the following analytical procedures:

  • Review the case to get an overview of the situation . A case can be only a few pages in length, however, it is most often very lengthy and contains a significant amount of detailed background information and statistics, with multilayered descriptions of the scenario, the roles and behaviors of various stakeholder groups, and situational events. Therefore, a quick reading of the case will help you gain an overall sense of the situation and illuminate the types of issues and problems that you will need to address in your paper. If your professor has provided questions intended to help frame your analysis, use them to guide your initial reading of the case.
  • Read the case thoroughly . After gaining a general overview of the case, carefully read the content again with the purpose of understanding key circumstances, events, and behaviors among stakeholder groups. Look for information or data that appears contradictory, extraneous, or misleading. At this point, you should be taking notes as you read because this will help you develop a general outline of your paper. The aim is to obtain a complete understanding of the situation so that you can begin contemplating tentative answers to any questions your professor has provided or, if they have not provided, developing answers to your own questions about the case scenario and its connection to the course readings,lectures, and class discussions.
  • Determine key stakeholder groups, issues, and events and the relationships they all have to each other . As you analyze the content, pay particular attention to identifying individuals, groups, or organizations described in the case and identify evidence of any problems or issues of concern that impact the situation in a negative way. Other things to look for include identifying any assumptions being made by or about each stakeholder, potential biased explanations or actions, explicit demands or ultimatums , and the underlying concerns that motivate these behaviors among stakeholders. The goal at this stage is to develop a comprehensive understanding of the situational and behavioral dynamics of the case and the explicit and implicit consequences of each of these actions.
  • Identify the core problems . The next step in most case analysis assignments is to discern what the core [i.e., most damaging, detrimental, injurious] problems are within the organizational setting and to determine their implications. The purpose at this stage of preparing to write your analysis paper is to distinguish between the symptoms of core problems and the core problems themselves and to decide which of these must be addressed immediately and which problems do not appear critical but may escalate over time. Identify evidence from the case to support your decisions by determining what information or data is essential to addressing the core problems and what information is not relevant or is misleading.
  • Explore alternative solutions . As noted, case analysis scenarios rarely have only one correct answer. Therefore, it is important to keep in mind that the process of analyzing the case and diagnosing core problems, while based on evidence, is a subjective process open to various avenues of interpretation. This means that you must consider alternative solutions or courses of action by critically examining strengths and weaknesses, risk factors, and the differences between short and long-term solutions. For each possible solution or course of action, consider the consequences they may have related to their implementation and how these recommendations might lead to new problems. Also, consider thinking about your recommended solutions or courses of action in relation to issues of fairness, equity, and inclusion.
  • Decide on a final set of recommendations . The last stage in preparing to write a case analysis paper is to assert an opinion or viewpoint about the recommendations needed to help resolve the core problems as you see them and to make a persuasive argument for supporting this point of view. Prepare a clear rationale for your recommendations based on examining each element of your analysis. Anticipate possible obstacles that could derail their implementation. Consider any counter-arguments that could be made concerning the validity of your recommended actions. Finally, describe a set of criteria and measurable indicators that could be applied to evaluating the effectiveness of your implementation plan.

Use these steps as the framework for writing your paper. Remember that the more detailed you are in taking notes as you critically examine each element of the case, the more information you will have to draw from when you begin to write. This will save you time.

NOTE : If the process of preparing to write a case analysis paper is assigned as a student group project, consider having each member of the group analyze a specific element of the case, including drafting answers to the corresponding questions used by your professor to frame the analysis. This will help make the analytical process more efficient and ensure that the distribution of work is equitable. This can also facilitate who is responsible for drafting each part of the final case analysis paper and, if applicable, the in-class presentation.

Framework for Case Analysis . College of Management. University of Massachusetts; Hawes, Jon M. "Teaching is Not Telling: The Case Method as a Form of Interactive Learning." Journal for Advancement of Marketing Education 5 (Winter 2004): 47-54; Rasche, Christoph and Achim Seisreiner. Guidelines for Business Case Analysis . University of Potsdam; Writing a Case Study Analysis . University of Arizona Global Campus Writing Center; Van Ness, Raymond K. A Guide to Case Analysis . School of Business. State University of New York, Albany; Writing a Case Analysis . Business School, University of New South Wales.

Structure and Writing Style

A case analysis paper should be detailed, concise, persuasive, clearly written, and professional in tone and in the use of language . As with other forms of college-level academic writing, declarative statements that convey information, provide a fact, or offer an explanation or any recommended courses of action should be based on evidence. If allowed by your professor, any external sources used to support your analysis, such as course readings, should be properly cited under a list of references. The organization and structure of case analysis papers can vary depending on your professor’s preferred format, but its structure generally follows the steps used for analyzing the case.

Introduction

The introduction should provide a succinct but thorough descriptive overview of the main facts, issues, and core problems of the case . The introduction should also include a brief summary of the most relevant details about the situation and organizational setting. This includes defining the theoretical framework or conceptual model on which any questions were used to frame your analysis.

Following the rules of most college-level research papers, the introduction should then inform the reader how the paper will be organized. This includes describing the major sections of the paper and the order in which they will be presented. Unless you are told to do so by your professor, you do not need to preview your final recommendations in the introduction. U nlike most college-level research papers , the introduction does not include a statement about the significance of your findings because a case analysis assignment does not involve contributing new knowledge about a research problem.

Background Analysis

Background analysis can vary depending on any guiding questions provided by your professor and the underlying concept or theory that the case is based upon. In general, however, this section of your paper should focus on:

  • Providing an overarching analysis of problems identified from the case scenario, including identifying events that stakeholders find challenging or troublesome,
  • Identifying assumptions made by each stakeholder and any apparent biases they may exhibit,
  • Describing any demands or claims made by or forced upon key stakeholders, and
  • Highlighting any issues of concern or complaints expressed by stakeholders in response to those demands or claims.

These aspects of the case are often in the form of behavioral responses expressed by individuals or groups within the organizational setting. However, note that problems in a case situation can also be reflected in data [or the lack thereof] and in the decision-making, operational, cultural, or institutional structure of the organization. Additionally, demands or claims can be either internal and external to the organization [e.g., a case analysis involving a president considering arms sales to Saudi Arabia could include managing internal demands from White House advisors as well as demands from members of Congress].

Throughout this section, present all relevant evidence from the case that supports your analysis. Do not simply claim there is a problem, an assumption, a demand, or a concern; tell the reader what part of the case informed how you identified these background elements.

Identification of Problems

In most case analysis assignments, there are problems, and then there are problems . Each problem can reflect a multitude of underlying symptoms that are detrimental to the interests of the organization. The purpose of identifying problems is to teach students how to differentiate between problems that vary in severity, impact, and relative importance. Given this, problems can be described in three general forms: those that must be addressed immediately, those that should be addressed but the impact is not severe, and those that do not require immediate attention and can be set aside for the time being.

All of the problems you identify from the case should be identified in this section of your paper, with a description based on evidence explaining the problem variances. If the assignment asks you to conduct research to further support your assessment of the problems, include this in your explanation. Remember to cite those sources in a list of references. Use specific evidence from the case and apply appropriate concepts, theories, and models discussed in class or in relevant course readings to highlight and explain the key problems [or problem] that you believe must be solved immediately and describe the underlying symptoms and why they are so critical.

Alternative Solutions

This section is where you provide specific, realistic, and evidence-based solutions to the problems you have identified and make recommendations about how to alleviate the underlying symptomatic conditions impacting the organizational setting. For each solution, you must explain why it was chosen and provide clear evidence to support your reasoning. This can include, for example, course readings and class discussions as well as research resources, such as, books, journal articles, research reports, or government documents. In some cases, your professor may encourage you to include personal, anecdotal experiences as evidence to support why you chose a particular solution or set of solutions. Using anecdotal evidence helps promote reflective thinking about the process of determining what qualifies as a core problem and relevant solution .

Throughout this part of the paper, keep in mind the entire array of problems that must be addressed and describe in detail the solutions that might be implemented to resolve these problems.

Recommended Courses of Action

In some case analysis assignments, your professor may ask you to combine the alternative solutions section with your recommended courses of action. However, it is important to know the difference between the two. A solution refers to the answer to a problem. A course of action refers to a procedure or deliberate sequence of activities adopted to proactively confront a situation, often in the context of accomplishing a goal. In this context, proposed courses of action are based on your analysis of alternative solutions. Your description and justification for pursuing each course of action should represent the overall plan for implementing your recommendations.

For each course of action, you need to explain the rationale for your recommendation in a way that confronts challenges, explains risks, and anticipates any counter-arguments from stakeholders. Do this by considering the strengths and weaknesses of each course of action framed in relation to how the action is expected to resolve the core problems presented, the possible ways the action may affect remaining problems, and how the recommended action will be perceived by each stakeholder.

In addition, you should describe the criteria needed to measure how well the implementation of these actions is working and explain which individuals or groups are responsible for ensuring your recommendations are successful. In addition, always consider the law of unintended consequences. Outline difficulties that may arise in implementing each course of action and describe how implementing the proposed courses of action [either individually or collectively] may lead to new problems [both large and small].

Throughout this section, you must consider the costs and benefits of recommending your courses of action in relation to uncertainties or missing information and the negative consequences of success.

The conclusion should be brief and introspective. Unlike a research paper, the conclusion in a case analysis paper does not include a summary of key findings and their significance, a statement about how the study contributed to existing knowledge, or indicate opportunities for future research.

Begin by synthesizing the core problems presented in the case and the relevance of your recommended solutions. This can include an explanation of what you have learned about the case in the context of your answers to the questions provided by your professor. The conclusion is also where you link what you learned from analyzing the case with the course readings or class discussions. This can further demonstrate your understanding of the relationships between the practical case situation and the theoretical and abstract content of assigned readings and other course content.

Problems to Avoid

The literature on case analysis assignments often includes examples of difficulties students have with applying methods of critical analysis and effectively reporting the results of their assessment of the situation. A common reason cited by scholars is that the application of this type of teaching and learning method is limited to applied fields of social and behavioral sciences and, as a result, writing a case analysis paper can be unfamiliar to most students entering college.

After you have drafted your paper, proofread the narrative flow and revise any of these common errors:

  • Unnecessary detail in the background section . The background section should highlight the essential elements of the case based on your analysis. Focus on summarizing the facts and highlighting the key factors that become relevant in the other sections of the paper by eliminating any unnecessary information.
  • Analysis relies too much on opinion . Your analysis is interpretive, but the narrative must be connected clearly to evidence from the case and any models and theories discussed in class or in course readings. Any positions or arguments you make should be supported by evidence.
  • Analysis does not focus on the most important elements of the case . Your paper should provide a thorough overview of the case. However, the analysis should focus on providing evidence about what you identify are the key events, stakeholders, issues, and problems. Emphasize what you identify as the most critical aspects of the case to be developed throughout your analysis. Be thorough but succinct.
  • Writing is too descriptive . A paper with too much descriptive information detracts from your analysis of the complexities of the case situation. Questions about what happened, where, when, and by whom should only be included as essential information leading to your examination of questions related to why, how, and for what purpose.
  • Inadequate definition of a core problem and associated symptoms . A common error found in case analysis papers is recommending a solution or course of action without adequately defining or demonstrating that you understand the problem. Make sure you have clearly described the problem and its impact and scope within the organizational setting. Ensure that you have adequately described the root causes w hen describing the symptoms of the problem.
  • Recommendations lack specificity . Identify any use of vague statements and indeterminate terminology, such as, “A particular experience” or “a large increase to the budget.” These statements cannot be measured and, as a result, there is no way to evaluate their successful implementation. Provide specific data and use direct language in describing recommended actions.
  • Unrealistic, exaggerated, or unattainable recommendations . Review your recommendations to ensure that they are based on the situational facts of the case. Your recommended solutions and courses of action must be based on realistic assumptions and fit within the constraints of the situation. Also note that the case scenario has already happened, therefore, any speculation or arguments about what could have occurred if the circumstances were different should be revised or eliminated.

Bee, Lian Song et al. "Business Students' Perspectives on Case Method Coaching for Problem-Based Learning: Impacts on Student Engagement and Learning Performance in Higher Education." Education & Training 64 (2022): 416-432; The Case Analysis . Fred Meijer Center for Writing and Michigan Authors. Grand Valley State University; Georgallis, Panikos and Kayleigh Bruijn. "Sustainability Teaching using Case-Based Debates." Journal of International Education in Business 15 (2022): 147-163; Hawes, Jon M. "Teaching is Not Telling: The Case Method as a Form of Interactive Learning." Journal for Advancement of Marketing Education 5 (Winter 2004): 47-54; Georgallis, Panikos, and Kayleigh Bruijn. "Sustainability Teaching Using Case-based Debates." Journal of International Education in Business 15 (2022): 147-163; .Dean,  Kathy Lund and Charles J. Fornaciari. "How to Create and Use Experiential Case-Based Exercises in a Management Classroom." Journal of Management Education 26 (October 2002): 586-603; Klebba, Joanne M. and Janet G. Hamilton. "Structured Case Analysis: Developing Critical Thinking Skills in a Marketing Case Course." Journal of Marketing Education 29 (August 2007): 132-137, 139; Klein, Norman. "The Case Discussion Method Revisited: Some Questions about Student Skills." Exchange: The Organizational Behavior Teaching Journal 6 (November 1981): 30-32; Mukherjee, Arup. "Effective Use of In-Class Mini Case Analysis for Discovery Learning in an Undergraduate MIS Course." The Journal of Computer Information Systems 40 (Spring 2000): 15-23; Pessoa, Silviaet al. "Scaffolding the Case Analysis in an Organizational Behavior Course: Making Analytical Language Explicit." Journal of Management Education 46 (2022): 226-251: Ramsey, V. J. and L. D. Dodge. "Case Analysis: A Structured Approach." Exchange: The Organizational Behavior Teaching Journal 6 (November 1981): 27-29; Schweitzer, Karen. "How to Write and Format a Business Case Study." ThoughtCo. https://www.thoughtco.com/how-to-write-and-format-a-business-case-study-466324 (accessed December 5, 2022); Reddy, C. D. "Teaching Research Methodology: Everything's a Case." Electronic Journal of Business Research Methods 18 (December 2020): 178-188; Volpe, Guglielmo. "Case Teaching in Economics: History, Practice and Evidence." Cogent Economics and Finance 3 (December 2015). doi:https://doi.org/10.1080/23322039.2015.1120977.

Writing Tip

Ca se Study and Case Analysis Are Not the Same!

Confusion often exists between what it means to write a paper that uses a case study research design and writing a paper that analyzes a case; they are two different types of approaches to learning in the social and behavioral sciences. Professors as well as educational researchers contribute to this confusion because they often use the term "case study" when describing the subject of analysis for a case analysis paper. But you are not studying a case for the purpose of generating a comprehensive, multi-faceted understanding of a research problem. R ather, you are critically analyzing a specific scenario to argue logically for recommended solutions and courses of action that lead to optimal outcomes applicable to professional practice.

To avoid any confusion, here are twelve characteristics that delineate the differences between writing a paper using the case study research method and writing a case analysis paper:

  • Case study is a method of in-depth research and rigorous inquiry ; case analysis is a reliable method of teaching and learning . A case study is a modality of research that investigates a phenomenon for the purpose of creating new knowledge, solving a problem, or testing a hypothesis using empirical evidence derived from the case being studied. Often, the results are used to generalize about a larger population or within a wider context. The writing adheres to the traditional standards of a scholarly research study. A case analysis is a pedagogical tool used to teach students how to reflect and think critically about a practical, real-life problem in an organizational setting.
  • The researcher is responsible for identifying the case to study; a case analysis is assigned by your professor . As the researcher, you choose the case study to investigate in support of obtaining new knowledge and understanding about the research problem. The case in a case analysis assignment is almost always provided, and sometimes written, by your professor and either given to every student in class to analyze individually or to a small group of students, or students select a case to analyze from a predetermined list.
  • A case study is indeterminate and boundless; a case analysis is predetermined and confined . A case study can be almost anything [see item 9 below] as long as it relates directly to examining the research problem. This relationship is the only limit to what a researcher can choose as the subject of their case study. The content of a case analysis is determined by your professor and its parameters are well-defined and limited to elucidating insights of practical value applied to practice.
  • Case study is fact-based and describes actual events or situations; case analysis can be entirely fictional or adapted from an actual situation . The entire content of a case study must be grounded in reality to be a valid subject of investigation in an empirical research study. A case analysis only needs to set the stage for critically examining a situation in practice and, therefore, can be entirely fictional or adapted, all or in-part, from an actual situation.
  • Research using a case study method must adhere to principles of intellectual honesty and academic integrity; a case analysis scenario can include misleading or false information . A case study paper must report research objectively and factually to ensure that any findings are understood to be logically correct and trustworthy. A case analysis scenario may include misleading or false information intended to deliberately distract from the central issues of the case. The purpose is to teach students how to sort through conflicting or useless information in order to come up with the preferred solution. Any use of misleading or false information in academic research is considered unethical.
  • Case study is linked to a research problem; case analysis is linked to a practical situation or scenario . In the social sciences, the subject of an investigation is most often framed as a problem that must be researched in order to generate new knowledge leading to a solution. Case analysis narratives are grounded in real life scenarios for the purpose of examining the realities of decision-making behavior and processes within organizational settings. A case analysis assignments include a problem or set of problems to be analyzed. However, the goal is centered around the act of identifying and evaluating courses of action leading to best possible outcomes.
  • The purpose of a case study is to create new knowledge through research; the purpose of a case analysis is to teach new understanding . Case studies are a choice of methodological design intended to create new knowledge about resolving a research problem. A case analysis is a mode of teaching and learning intended to create new understanding and an awareness of uncertainty applied to practice through acts of critical thinking and reflection.
  • A case study seeks to identify the best possible solution to a research problem; case analysis can have an indeterminate set of solutions or outcomes . Your role in studying a case is to discover the most logical, evidence-based ways to address a research problem. A case analysis assignment rarely has a single correct answer because one of the goals is to force students to confront the real life dynamics of uncertainly, ambiguity, and missing or conflicting information within professional practice. Under these conditions, a perfect outcome or solution almost never exists.
  • Case study is unbounded and relies on gathering external information; case analysis is a self-contained subject of analysis . The scope of a case study chosen as a method of research is bounded. However, the researcher is free to gather whatever information and data is necessary to investigate its relevance to understanding the research problem. For a case analysis assignment, your professor will often ask you to examine solutions or recommended courses of action based solely on facts and information from the case.
  • Case study can be a person, place, object, issue, event, condition, or phenomenon; a case analysis is a carefully constructed synopsis of events, situations, and behaviors . The research problem dictates the type of case being studied and, therefore, the design can encompass almost anything tangible as long as it fulfills the objective of generating new knowledge and understanding. A case analysis is in the form of a narrative containing descriptions of facts, situations, processes, rules, and behaviors within a particular setting and under a specific set of circumstances.
  • Case study can represent an open-ended subject of inquiry; a case analysis is a narrative about something that has happened in the past . A case study is not restricted by time and can encompass an event or issue with no temporal limit or end. For example, the current war in Ukraine can be used as a case study of how medical personnel help civilians during a large military conflict, even though circumstances around this event are still evolving. A case analysis can be used to elicit critical thinking about current or future situations in practice, but the case itself is a narrative about something finite and that has taken place in the past.
  • Multiple case studies can be used in a research study; case analysis involves examining a single scenario . Case study research can use two or more cases to examine a problem, often for the purpose of conducting a comparative investigation intended to discover hidden relationships, document emerging trends, or determine variations among different examples. A case analysis assignment typically describes a stand-alone, self-contained situation and any comparisons among cases are conducted during in-class discussions and/or student presentations.

The Case Analysis . Fred Meijer Center for Writing and Michigan Authors. Grand Valley State University; Mills, Albert J. , Gabrielle Durepos, and Eiden Wiebe, editors. Encyclopedia of Case Study Research . Thousand Oaks, CA: SAGE Publications, 2010; Ramsey, V. J. and L. D. Dodge. "Case Analysis: A Structured Approach." Exchange: The Organizational Behavior Teaching Journal 6 (November 1981): 27-29; Yin, Robert K. Case Study Research and Applications: Design and Methods . 6th edition. Thousand Oaks, CA: Sage, 2017; Crowe, Sarah et al. “The Case Study Approach.” BMC Medical Research Methodology 11 (2011):  doi: 10.1186/1471-2288-11-100; Yin, Robert K. Case Study Research: Design and Methods . 4th edition. Thousand Oaks, CA: Sage Publishing; 1994.

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What Is a Case Study and Why You Should Use Them

Case studies can provide more insights into your business while helping you conduct further research with robust qualitative data analysis to learn more.

If you're in charge of running a company, then you're likely always looking for new ways to run your business more efficiently and increase your customer base while streamlining as many processes as possible.

Unfortunately, it can sometimes be difficult to determine how to go about implementing the proper program in order to be successful. This is why many business owners opt to conduct a case study, which can help significantly. Whether you've been struggling with brand consistency or some other problem, the right case study can identify why your problem exists as well as provide a way to rectify it.

A case study is a great tool that many businesses aren't even aware exists, and there are marketing experts like Mailchimp who can provide you with step-by-step assistance with implementing a plan with a case study. Many companies discover that not only do they need to start a blog in order to improve business, but they also need to create specific and relevant blog titles.

If your company already has a blog, then optimizing your blog posts may be helpful. Regardless of the obstacles that are preventing you from achieving all your professional goals, a case study can work wonders in helping you reverse this issue.

case study potential problems

What is a case study?

A case study is a comprehensive report of the results of theory testing or examining emerging themes of a business in real life context. Case studies are also often used in the healthcare industry, conducting health services research with primary research interest around routinely collected healthcare data.

However, for businesses, the purpose of a case study is to help small business owners or company leaders identify the issues and conduct further research into what may be preventing success through information collection, client or customer interviews, and in-depth data analysis.

Knowing the case study definition is crucial for any business owner. By identifying the issues that are hindering a company from achieving all its goals, it's easier to make the necessary corrections to promote success through influenced data collection.

Why are case studies important?

Now that we've answered the questions, "what is a case study?" Why are case studies important? Some of the top reasons why case studies are important include:

 Importance of case studies

  • Understand complex issues: Even after you conduct a significant amount of market research , you might have a difficult time understanding exactly what it means. While you might have the basics down, conducting a case study can help you see how that information is applied. Then, when you see how the information can make a difference in business decisions, it could make it easier to understand complex issues.
  • Collect data: A case study can also help with data tracking . A case study is a data collection method that can help you describe the information that you have available to you. Then, you can present that information in a way the reader can understand.
  • Conduct evaluations: As you learn more about how to write a case study, remember that you can also use a case study to conduct evaluations of a specific situation. A case study is a great way to learn more about complex situations, and you can evaluate how various people responded in that situation. By conducting a case study evaluation, you can learn more about what has worked well, what has not, and what you might want to change in the future.
  • Identify potential solutions: A case study can also help you identify solutions to potential problems. If you have an issue in your business that you are trying to solve, you may be able to take a look at a case study where someone has dealt with a similar situation in the past. For example, you may uncover data bias in a specific solution that you would like to address when you tackle the issue on your own. If you need help solving a difficult problem, a case study may be able to help you.

Remember that you can also use case studies to target your audience . If you want to show your audience that you have a significant level of expertise in a field, you may want to publish some case studies that you have handled in the past. Then, when your audience sees that you have had success in a specific area, they may be more likely to provide you with their business. In essence, case studies can be looked at as the original method of social proof, showcasing exactly how you can help someone solve their problems.

What are the benefits of writing a business case study?

Although writing a case study can seem like a tedious task, there are many benefits to conducting one through an in depth qualitative research process.

Benefits of Case Studies

  • Industry understanding: First of all, a case study can give you an in-depth understanding of your industry through a particular conceptual framework and help you identify hidden problems that are preventing you from transcending into the business world.
  • Develop theories: If you decide to write a business case study, it provides you with an opportunity to develop new theories. You might have a theory about how to solve a specific problem, but you need to write a business case study to see exactly how that theory has unfolded in the past. Then, you can figure out if you want to apply your theory to a similar issue in the future.
  • Evaluate interventions: When you write a business case study that focuses on a specific situation you have been through in the past, you can uncover whether that intervention was truly helpful. This can make it easier to figure out whether you want to use the same intervention in a similar situation in the future.
  • Identify best practices: If you want to stay on top of the best practices in your field, conducting case studies can help by allowing you to identify patterns and trends and develop a new list of best practices that you can follow in the future.
  • Versatility: Writing a case study also provides you with more versatility. If you want to expand your business applications, you need to figure out how you respond to various problems. When you run a business case study, you open the door to new opportunities, new applications, and new techniques that could help you make a difference in your business down the road.
  • Solve problems: Writing a great case study can dramatically improve your chances of reversing your problem and improving your business.
  • These are just a few of the biggest benefits you might experience if you decide to publish your case studies. They can be an effective tool for learning, showcasing your talents, and teaching some of your other employees. If you want to grow your audience , you may want to consider publishing some case studies.

What are the limitations of case studies?

Case studies can be a wonderful tool for any business of any size to use to gain an in-depth understanding of their clients, products, customers, or services, but there are limitations.

One limitation of case studies is the fact that, unless there are other recently published examples, there is nothing to compare them to since, most of the time, you are conducting a single, not multiple, case studies.

Another limitation is the fact that most case studies can lack scientific evidence.

case study potential problems

Types of case studies

There are specific types of case studies to choose from, and each specific type will yield different results. Some case study types even overlap, which is sometimes more favorable, as they provide even more pertinent data.

Here are overviews of the different types of case studies, each with its own theoretical framework, so you can determine which type would be most effective for helping you meet your goals.

Explanatory case studies

Explanatory case studies are pretty straightforward, as they're not difficult to interpret. This type of case study is best if there aren't many variables involved because explanatory case studies can easily answer questions like "how" and "why" through theory development.

Exploratory case studies

An exploratory case study does exactly what its name implies: it goes into specific detail about the topic at hand in a natural, real-life context with qualitative research.

The benefits of exploratory case studies are limitless, with the main one being that it offers a great deal of flexibility. Having flexibility when writing a case study is important because you can't always predict what obstacles might arise during the qualitative research process.

Collective case studies

Collective case studies require you to study many different individuals in order to obtain usable data.

Case studies that involve an investigation of people will involve many different variables, all of which can't be predicted. Despite this fact, there are many benefits of collective case studies, including the fact that it allows an ongoing analysis of the data collected.

Intrinsic case studies

This type of study differs from the others as it focuses on the inquiry of one specific instance among many possibilities.

Many people prefer these types of case studies because it allows them to learn about the particular instance that they wish to investigate further.

Instrumental case studies

An instrumental case study is similar to an intrinsic one, as it focuses on a particular instance, whether it's a person, organization, or something different.

One thing that differentiates instrumental case studies from intrinsic ones is the fact that instrumental case studies aren't chosen merely because a person is interested in learning about a specific instance.

case study potential problems

Tips for writing a case study

If you have decided to write case studies for your company, then you may be unsure of where to start or which type to conduct.

However, it doesn't have to be difficult or confusing to begin conducting a case study that will help you identify ways to improve your business.

Here are some helpful tips for writing your case studies:

1. Your case study must be written in the proper format

When writing a case study, the format that you should be similar to this:

Case study format

Administrative summary

The executive summary is an overview of what your report will contain, written in a concise manner while providing real-life context.

Despite the fact that the executive summary should appear at the beginning of your case studies, it shouldn't be written until you've completed the entire report because if you write it before you finish the report, this summary may not be completely accurate.

Key problem statement

In this section of your case study, you will briefly describe the problem that you hope to solve by conducting the study. You will have the opportunity to elaborate on the problem that you're focusing on as you get into the breadth of the report.

Problem exploration

This part of the case study isn't as brief as the other two, and it goes into more detail about the problem at hand. Your problem exploration must include why the identified problem needs to be solved as well as the urgency of solving it.

Additionally, it must include justification for conducting the problem-solving, as the benefits must outweigh the efforts and costs.

Proposed resolution

This case study section will also be lengthier than the first two. It must include how you propose going about rectifying the problem. The "recommended solution" section must also include potential obstacles that you might experience, as well as how these will be managed.

Furthermore, you will need to list alternative solutions and explain the reason the chosen solution is best. Charts can enhance your report and make it easier to read, and provide as much proof to substantiate your claim as possible.

Overview of monetary consideration

An overview of monetary consideration is essential for all case studies, as it will be used to convince all involved parties why your project should be funded. You must successfully convince them that the cost is worth the investment it will require. It's important that you stress the necessity for this particular case study and explain the expected outcome.

Execution timeline

In the execution times of case studies, you explain how long you predict it will take to implement your study. The shorter the time it will take to implement your plan, the more apt it is to be approved. However, be sure to provide a reasonable timeline, taking into consideration any additional time that might be needed due to obstacles.

Always include a conclusion in your case study. This is where you will briefly wrap up your entire proposal, stressing the benefits of completing the data collection and data analysis in order to rectify your problem.

2. Make it clear and comprehensive

You want to write your case studies with as much clarity as possible so that every aspect of the report is understood. Be sure to double-check your grammar, spelling, punctuation, and more, as you don't want to submit a poorly-written document.

Not only would a poorly-written case study fail to prove that what you are trying to achieve is important, but it would also increase the chances that your report will be tossed aside and not taken seriously.

3. Don't rush through the process

Writing the perfect case study takes time and patience. Rushing could result in your forgetting to include information that is crucial to your entire study. Don't waste your time creating a study that simply isn't ready. Take the necessary time to perform all the research necessary to write the best case study possible.

Depending on the case study, conducting case study research could mean using qualitative methods, quantitative methods, or both. Qualitative research questions focus on non-numerical data, such as how people feel, their beliefs, their experiences, and so on.

Meanwhile, quantitative research questions focus on numerical or statistical data collection to explain causal links or get an in-depth picture.

It is also important to collect insightful and constructive feedback. This will help you better understand the outcome as well as any changes you need to make to future case studies. Consider using formal and informal ways to collect feedback to ensure that you get a range of opinions and perspectives.

4. Be confident in your theory development

While writing your case study or conducting your formal experimental investigation, you should have confidence in yourself and what you're proposing in your report. If you took the time to gather all the pertinent data collected to complete the report, don't second-guess yourself or doubt your abilities. If you believe your report will be amazing, then it likely will be.

5. Case studies and all qualitative research are long

It's expected that multiple case studies are going to be incredibly boring, and there is no way around this. However, it doesn't mean you can choose your language carefully in order to keep your audience as engaged as possible.

If your audience loses interest in your case study at the beginning, for whatever reason, then this increases the likelihood that your case study will not be funded.

Case study examples

If you want to learn more about how to write a case study, it might be beneficial to take a look at a few case study examples. Below are a few interesting case study examples you may want to take a closer look at.

  • Phineas Gage by John Martin Marlow : One of the most famous case studies comes from the medical field, and it is about the story of Phineas Gage, a man who had a railroad spike driven through his head in 1848. As he was working on a railroad, an explosive charge went off prematurely, sending a railroad rod through his head. Even though he survived this incident, he lost his left eye. However, Phineas Gage was studied extensively over the years because his experiences had a significant, lasting impact on his personality. This served as a case study because his injury showed different parts of the brain have different functions.
  • Kitty Genovese and the bystander effect : This is a tragic case study that discusses the murder of Kitty Genovese, a woman attacked and murdered in Queens, New York City. Shockingly, while numerous neighbors watched the scene, nobody called for help because they assumed someone else would. This case study helped to define the bystander effect, which is when a person fails to intervene during an emergency because other people are around.
  • Henry Molaison and the study of memory : Henry Molaison lost his memory and suffered from debilitating amnesia. He suffered from childhood epilepsy, and medical professionals attempted to remove the part of his brain that was causing his seizures. He had a portion of his brain removed, but it completely took away his ability to hold memories. Even though he went on to live until the age of 82, he was always forced to live in the present moment, as he was completely unable to form new memories.

Case study FAQs

When should you do a case study.

There are several scenarios when conducting a case study can be beneficial. Case studies are often used when there's a "why" or "how" question that needs to be answered. Case studies are also beneficial when trying to understand a complex phenomenon, there's limited research on a topic, or when you're looking for practical solutions to a problem.

How can case study results be used to make business decisions?

You can use the results from a case study to make future business decisions if you find yourself in a similar situation. As you assess the results of a case study, you can identify best practices, evaluate the effectiveness of an intervention, generate new and creative ideas, or get a better understanding of customer needs.

How are case studies different from other research methodologies?

When compared to other research methodologies, such as experimental or qualitative research methodology, a case study does not require a representative sample. For example, if you are performing quantitative research, you have a lot of subjects that expand your sample size. If you are performing experimental research, you may have a random sample in front of you. A case study is usually designed to deliberately focus on unusual situations, which allows it to shed new light on a specific business research problem.

Writing multiple case studies for your business

If you're feeling overwhelmed by the idea of writing a case study and it seems completely foreign, then you aren't alone. Writing a case study for a business is a very big deal, but fortunately, there is help available because an example of a case study doesn't always help.

Mailchimp, a well-known marketing company that provides comprehensive marketing support for all sorts of businesses, can assist you with your case study, or you can review one of their own recently published examples.

Mailchimp can assist you with developing the most effective content strategy to increase your chances of being as successful as possible. Mailchimp's content studio is a great tool that can help your business immensely.

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Potential Problem Analysis

A potential problem analysis (PPA) is a systematic method for determining what could go wrong in a plan under development. The problem causes are rated according to their likelihood of occurrence and the severity of their consequences. Preventive actions are taken and contingency plans are developed. The process helps to create a smooth, streamlined implementation process.

Prior to the implementation of a plan.

When a problem may occur.

When the schedule for the plan's completion is significant.

When there is a high cost of failure.

When working with a large or complicated plan.

1. IDENTIFY BROAD ASPECTS of the plan that may be prone to failure.

2. IDENTIFY SPECIFIC PROBLEMS that could occur and record them in the first column of a table.

3. ESTIMATE THE RISK of each problem by assigning it a high, medium, or low rating for both its likelihood and the severity of its consequences.

4. IDENTIFY POSSIBLE CAUSES and record them in the second column.

5. (Optional) For each cause, RATE AS HIGH, MEDIUM, OR LOW its likelihood and the severity of its occurrence in a column headed P (probability) and S, respectively.

6. For each cause IDENTIFY PREVENTATIVE ACTIONS to prevent or reduce the likelihood that the cause will occur. Record it in the fifth column and rate the residual risk, the likelihood, and severity of the cause with the preventive action in place. Record this data in the next column.

7. DEVELOP A CONTINGENCY PLAN to minimize the consequences of causes with unacceptable residual risk, should the preventive action fail to work. Write this plan in the final column.

Addresses causes, evaluates risk, and keeps preventive actions and contingency plans separate.

Only identifies and addresses transparent problems.

Tague N. The tools. In: O'Mara P, editor. The quality toolbox. 2nd ed. Milwaukee, WI: ASQ Quality Press; 2005. p. 93-521.

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Hertz CEO Kathryn Marinello with CFO Jamere Jackson and other members of the executive team in 2017

Top 40 Most Popular Case Studies of 2021

Two cases about Hertz claimed top spots in 2021's Top 40 Most Popular Case Studies

Two cases on the uses of debt and equity at Hertz claimed top spots in the CRDT’s (Case Research and Development Team) 2021 top 40 review of cases.

Hertz (A) took the top spot. The case details the financial structure of the rental car company through the end of 2019. Hertz (B), which ranked third in CRDT’s list, describes the company’s struggles during the early part of the COVID pandemic and its eventual need to enter Chapter 11 bankruptcy. 

The success of the Hertz cases was unprecedented for the top 40 list. Usually, cases take a number of years to gain popularity, but the Hertz cases claimed top spots in their first year of release. Hertz (A) also became the first ‘cooked’ case to top the annual review, as all of the other winners had been web-based ‘raw’ cases.

Besides introducing students to the complicated financing required to maintain an enormous fleet of cars, the Hertz cases also expanded the diversity of case protagonists. Kathyrn Marinello was the CEO of Hertz during this period and the CFO, Jamere Jackson is black.

Sandwiched between the two Hertz cases, Coffee 2016, a perennial best seller, finished second. “Glory, Glory, Man United!” a case about an English football team’s IPO made a surprise move to number four.  Cases on search fund boards, the future of malls,  Norway’s Sovereign Wealth fund, Prodigy Finance, the Mayo Clinic, and Cadbury rounded out the top ten.

Other year-end data for 2021 showed:

  • Online “raw” case usage remained steady as compared to 2020 with over 35K users from 170 countries and all 50 U.S. states interacting with 196 cases.
  • Fifty four percent of raw case users came from outside the U.S..
  • The Yale School of Management (SOM) case study directory pages received over 160K page views from 177 countries with approximately a third originating in India followed by the U.S. and the Philippines.
  • Twenty-six of the cases in the list are raw cases.
  • A third of the cases feature a woman protagonist.
  • Orders for Yale SOM case studies increased by almost 50% compared to 2020.
  • The top 40 cases were supervised by 19 different Yale SOM faculty members, several supervising multiple cases.

CRDT compiled the Top 40 list by combining data from its case store, Google Analytics, and other measures of interest and adoption.

All of this year’s Top 40 cases are available for purchase from the Yale Management Media store .

And the Top 40 cases studies of 2021 are:

1.   Hertz Global Holdings (A): Uses of Debt and Equity

2.   Coffee 2016

3.   Hertz Global Holdings (B): Uses of Debt and Equity 2020

4.   Glory, Glory Man United!

5.   Search Fund Company Boards: How CEOs Can Build Boards to Help Them Thrive

6.   The Future of Malls: Was Decline Inevitable?

7.   Strategy for Norway's Pension Fund Global

8.   Prodigy Finance

9.   Design at Mayo

10. Cadbury

11. City Hospital Emergency Room

13. Volkswagen

14. Marina Bay Sands

15. Shake Shack IPO

16. Mastercard

17. Netflix

18. Ant Financial

19. AXA: Creating the New CR Metrics

20. IBM Corporate Service Corps

21. Business Leadership in South Africa's 1994 Reforms

22. Alternative Meat Industry

23. Children's Premier

24. Khalil Tawil and Umi (A)

25. Palm Oil 2016

26. Teach For All: Designing a Global Network

27. What's Next? Search Fund Entrepreneurs Reflect on Life After Exit

28. Searching for a Search Fund Structure: A Student Takes a Tour of Various Options

30. Project Sammaan

31. Commonfund ESG

32. Polaroid

33. Connecticut Green Bank 2018: After the Raid

34. FieldFresh Foods

35. The Alibaba Group

36. 360 State Street: Real Options

37. Herman Miller

38. AgBiome

39. Nathan Cummings Foundation

40. Toyota 2010

How to write a case study — examples, templates, and tools

case study potential problems

It’s a marketer’s job to communicate the effectiveness of a product or service to potential and current customers to convince them to buy and keep business moving. One of the best methods for doing this is to share success stories that are relatable to prospects and customers based on their pain points, experiences, and overall needs.

That’s where case studies come in. Case studies are an essential part of a content marketing plan. These in-depth stories of customer experiences are some of the most effective at demonstrating the value of a product or service. Yet many marketers don’t use them, whether because of their regimented formats or the process of customer involvement and approval.

A case study is a powerful tool for showcasing your hard work and the success your customer achieved. But writing a great case study can be difficult if you’ve never done it before or if it’s been a while. This guide will show you how to write an effective case study and provide real-world examples and templates that will keep readers engaged and support your business.

In this article, you’ll learn:

What is a case study?

How to write a case study, case study templates, case study examples, case study tools.

A case study is the detailed story of a customer’s experience with a product or service that demonstrates their success and often includes measurable outcomes. Case studies are used in a range of fields and for various reasons, from business to academic research. They’re especially impactful in marketing as brands work to convince and convert consumers with relatable, real-world stories of actual customer experiences.

The best case studies tell the story of a customer’s success, including the steps they took, the results they achieved, and the support they received from a brand along the way. To write a great case study, you need to:

  • Celebrate the customer and make them — not a product or service — the star of the story.
  • Craft the story with specific audiences or target segments in mind so that the story of one customer will be viewed as relatable and actionable for another customer.
  • Write copy that is easy to read and engaging so that readers will gain the insights and messages intended.
  • Follow a standardized format that includes all of the essentials a potential customer would find interesting and useful.
  • Support all of the claims for success made in the story with data in the forms of hard numbers and customer statements.

Case studies are a type of review but more in depth, aiming to show — rather than just tell — the positive experiences that customers have with a brand. Notably, 89% of consumers read reviews before deciding to buy, and 79% view case study content as part of their purchasing process. When it comes to B2B sales, 52% of buyers rank case studies as an important part of their evaluation process.

Telling a brand story through the experience of a tried-and-true customer matters. The story is relatable to potential new customers as they imagine themselves in the shoes of the company or individual featured in the case study. Showcasing previous customers can help new ones see themselves engaging with your brand in the ways that are most meaningful to them.

Besides sharing the perspective of another customer, case studies stand out from other content marketing forms because they are based on evidence. Whether pulling from client testimonials or data-driven results, case studies tend to have more impact on new business because the story contains information that is both objective (data) and subjective (customer experience) — and the brand doesn’t sound too self-promotional.

89% of consumers read reviews before buying, 79% view case studies, and 52% of B2B buyers prioritize case studies in the evaluation process.

Case studies are unique in that there’s a fairly standardized format for telling a customer’s story. But that doesn’t mean there isn’t room for creativity. It’s all about making sure that teams are clear on the goals for the case study — along with strategies for supporting content and channels — and understanding how the story fits within the framework of the company’s overall marketing goals.

Here are the basic steps to writing a good case study.

1. Identify your goal

Start by defining exactly who your case study will be designed to help. Case studies are about specific instances where a company works with a customer to achieve a goal. Identify which customers are likely to have these goals, as well as other needs the story should cover to appeal to them.

The answer is often found in one of the buyer personas that have been constructed as part of your larger marketing strategy. This can include anything from new leads generated by the marketing team to long-term customers that are being pressed for cross-sell opportunities. In all of these cases, demonstrating value through a relatable customer success story can be part of the solution to conversion.

2. Choose your client or subject

Who you highlight matters. Case studies tie brands together that might otherwise not cross paths. A writer will want to ensure that the highlighted customer aligns with their own company’s brand identity and offerings. Look for a customer with positive name recognition who has had great success with a product or service and is willing to be an advocate.

The client should also match up with the identified target audience. Whichever company or individual is selected should be a reflection of other potential customers who can see themselves in similar circumstances, having the same problems and possible solutions.

Some of the most compelling case studies feature customers who:

  • Switch from one product or service to another while naming competitors that missed the mark.
  • Experience measurable results that are relatable to others in a specific industry.
  • Represent well-known brands and recognizable names that are likely to compel action.
  • Advocate for a product or service as a champion and are well-versed in its advantages.

Whoever or whatever customer is selected, marketers must ensure they have the permission of the company involved before getting started. Some brands have strict review and approval procedures for any official marketing or promotional materials that include their name. Acquiring those approvals in advance will prevent any miscommunication or wasted effort if there is an issue with their legal or compliance teams.

3. Conduct research and compile data

Substantiating the claims made in a case study — either by the marketing team or customers themselves — adds validity to the story. To do this, include data and feedback from the client that defines what success looks like. This can be anything from demonstrating return on investment (ROI) to a specific metric the customer was striving to improve. Case studies should prove how an outcome was achieved and show tangible results that indicate to the customer that your solution is the right one.

This step could also include customer interviews. Make sure that the people being interviewed are key stakeholders in the purchase decision or deployment and use of the product or service that is being highlighted. Content writers should work off a set list of questions prepared in advance. It can be helpful to share these with the interviewees beforehand so they have time to consider and craft their responses. One of the best interview tactics to keep in mind is to ask questions where yes and no are not natural answers. This way, your subject will provide more open-ended responses that produce more meaningful content.

4. Choose the right format

There are a number of different ways to format a case study. Depending on what you hope to achieve, one style will be better than another. However, there are some common elements to include, such as:

  • An engaging headline
  • A subject and customer introduction
  • The unique challenge or challenges the customer faced
  • The solution the customer used to solve the problem
  • The results achieved
  • Data and statistics to back up claims of success
  • A strong call to action (CTA) to engage with the vendor

It’s also important to note that while case studies are traditionally written as stories, they don’t have to be in a written format. Some companies choose to get more creative with their case studies and produce multimedia content, depending on their audience and objectives. Case study formats can include traditional print stories, interactive web or social content, data-heavy infographics, professionally shot videos, podcasts, and more.

5. Write your case study

We’ll go into more detail later about how exactly to write a case study, including templates and examples. Generally speaking, though, there are a few things to keep in mind when writing your case study.

  • Be clear and concise. Readers want to get to the point of the story quickly and easily, and they’ll be looking to see themselves reflected in the story right from the start.
  • Provide a big picture. Always make sure to explain who the client is, their goals, and how they achieved success in a short introduction to engage the reader.
  • Construct a clear narrative. Stick to the story from the perspective of the customer and what they needed to solve instead of just listing product features or benefits.
  • Leverage graphics. Incorporating infographics, charts, and sidebars can be a more engaging and eye-catching way to share key statistics and data in readable ways.
  • Offer the right amount of detail. Most case studies are one or two pages with clear sections that a reader can skim to find the information most important to them.
  • Include data to support claims. Show real results — both facts and figures and customer quotes — to demonstrate credibility and prove the solution works.

6. Promote your story

Marketers have a number of options for distribution of a freshly minted case study. Many brands choose to publish case studies on their website and post them on social media. This can help support SEO and organic content strategies while also boosting company credibility and trust as visitors see that other businesses have used the product or service.

Marketers are always looking for quality content they can use for lead generation. Consider offering a case study as gated content behind a form on a landing page or as an offer in an email message. One great way to do this is to summarize the content and tease the full story available for download after the user takes an action.

Sales teams can also leverage case studies, so be sure they are aware that the assets exist once they’re published. Especially when it comes to larger B2B sales, companies often ask for examples of similar customer challenges that have been solved.

Now that you’ve learned a bit about case studies and what they should include, you may be wondering how to start creating great customer story content. Here are a couple of templates you can use to structure your case study.

Template 1 — Challenge-solution-result format

  • Start with an engaging title. This should be fewer than 70 characters long for SEO best practices. One of the best ways to approach the title is to include the customer’s name and a hint at the challenge they overcame in the end.
  • Create an introduction. Lead with an explanation as to who the customer is, the need they had, and the opportunity they found with a specific product or solution. Writers can also suggest the success the customer experienced with the solution they chose.
  • Present the challenge. This should be several paragraphs long and explain the problem the customer faced and the issues they were trying to solve. Details should tie into the company’s products and services naturally. This section needs to be the most relatable to the reader so they can picture themselves in a similar situation.
  • Share the solution. Explain which product or service offered was the ideal fit for the customer and why. Feel free to delve into their experience setting up, purchasing, and onboarding the solution.
  • Explain the results. Demonstrate the impact of the solution they chose by backing up their positive experience with data. Fill in with customer quotes and tangible, measurable results that show the effect of their choice.
  • Ask for action. Include a CTA at the end of the case study that invites readers to reach out for more information, try a demo, or learn more — to nurture them further in the marketing pipeline. What you ask of the reader should tie directly into the goals that were established for the case study in the first place.

Template 2 — Data-driven format

  • Start with an engaging title. Be sure to include a statistic or data point in the first 70 characters. Again, it’s best to include the customer’s name as part of the title.
  • Create an overview. Share the customer’s background and a short version of the challenge they faced. Present the reason a particular product or service was chosen, and feel free to include quotes from the customer about their selection process.
  • Present data point 1. Isolate the first metric that the customer used to define success and explain how the product or solution helped to achieve this goal. Provide data points and quotes to substantiate the claim that success was achieved.
  • Present data point 2. Isolate the second metric that the customer used to define success and explain what the product or solution did to achieve this goal. Provide data points and quotes to substantiate the claim that success was achieved.
  • Present data point 3. Isolate the final metric that the customer used to define success and explain what the product or solution did to achieve this goal. Provide data points and quotes to substantiate the claim that success was achieved.
  • Summarize the results. Reiterate the fact that the customer was able to achieve success thanks to a specific product or service. Include quotes and statements that reflect customer satisfaction and suggest they plan to continue using the solution.
  • Ask for action. Include a CTA at the end of the case study that asks readers to reach out for more information, try a demo, or learn more — to further nurture them in the marketing pipeline. Again, remember that this is where marketers can look to convert their content into action with the customer.

While templates are helpful, seeing a case study in action can also be a great way to learn. Here are some examples of how Adobe customers have experienced success.

Juniper Networks

One example is the Adobe and Juniper Networks case study , which puts the reader in the customer’s shoes. The beginning of the story quickly orients the reader so that they know exactly who the article is about and what they were trying to achieve. Solutions are outlined in a way that shows Adobe Experience Manager is the best choice and a natural fit for the customer. Along the way, quotes from the client are incorporated to help add validity to the statements. The results in the case study are conveyed with clear evidence of scale and volume using tangible data.

A Lenovo case study showing statistics, a pull quote and featured headshot, the headline "The customer is king.," and Adobe product links.

The story of Lenovo’s journey with Adobe is one that spans years of planning, implementation, and rollout. The Lenovo case study does a great job of consolidating all of this into a relatable journey that other enterprise organizations can see themselves taking, despite the project size. This case study also features descriptive headers and compelling visual elements that engage the reader and strengthen the content.

Tata Consulting

When it comes to using data to show customer results, this case study does an excellent job of conveying details and numbers in an easy-to-digest manner. Bullet points at the start break up the content while also helping the reader understand exactly what the case study will be about. Tata Consulting used Adobe to deliver elevated, engaging content experiences for a large telecommunications client of its own — an objective that’s relatable for a lot of companies.

Case studies are a vital tool for any marketing team as they enable you to demonstrate the value of your company’s products and services to others. They help marketers do their job and add credibility to a brand trying to promote its solutions by using the experiences and stories of real customers.

When you’re ready to get started with a case study:

  • Think about a few goals you’d like to accomplish with your content.
  • Make a list of successful clients that would be strong candidates for a case study.
  • Reach out to the client to get their approval and conduct an interview.
  • Gather the data to present an engaging and effective customer story.

Adobe can help

There are several Adobe products that can help you craft compelling case studies. Adobe Experience Platform helps you collect data and deliver great customer experiences across every channel. Once you’ve created your case studies, Experience Platform will help you deliver the right information to the right customer at the right time for maximum impact.

To learn more, watch the Adobe Experience Platform story .

Keep in mind that the best case studies are backed by data. That’s where Adobe Real-Time Customer Data Platform and Adobe Analytics come into play. With Real-Time CDP, you can gather the data you need to build a great case study and target specific customers to deliver the content to the right audience at the perfect moment.

Watch the Real-Time CDP overview video to learn more.

Finally, Adobe Analytics turns real-time data into real-time insights. It helps your business collect and synthesize data from multiple platforms to make more informed decisions and create the best case study possible.

Request a demo to learn more about Adobe Analytics.

https://business.adobe.com/blog/perspectives/b2b-ecommerce-10-case-studies-inspire-you

https://business.adobe.com/blog/basics/business-case

https://business.adobe.com/blog/basics/what-is-real-time-analytics

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Wilson P, Mathie E, Keenan J, et al. ReseArch with Patient and Public invOlvement: a RealisT evaluation – the RAPPORT study. Southampton (UK): NIHR Journals Library; 2015 Sep. (Health Services and Delivery Research, No. 3.38.)

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ReseArch with Patient and Public invOlvement: a RealisT evaluation – the RAPPORT study.

Chapter 6 findings from the case studies.

In this chapter we present the findings from the 22 case studies. We provide a rationale for why NPT was found to be the most comprehensive and predictive programme theory for PPI and present the 16 NPT informed mechanisms that were tested within the case studies. We then summarise the key findings and list the contexts that enabled mechanisms. CMO tables are provided, illustrating salient actions within the case studies, potential contexts, plausible mechanisms and potential outcomes. Organised under the major case study actions, data are presented to illustrate how the CMO tables were arrived at. We draw on specific case studies, including their NPT radar plots, to provide illustrative exemplars. The chapter concludes with evidence of PPI impact and outcomes.

  • Normalisation Process Theory as the candidate programme theory being tested

Our testing within case studies was framed by the 16 NPT mechanisms grouped under the four headings (see Chapter 3 ) and presented in Table 11 . When applied to the 22 case studies, NPT 121 , 134 had sufficient explanatory power to predict which case studies had PPI embedded as normal practice; therefore, it predicted both policy outcomes and the processes and infrastructure required for effective PPI that had positive outcomes both methodologically and morally. Using NPT as a MRT developed out of health service research, we directly interpreted PPI as the complex intervention, which then shaped our data collection tools and analytical framework (see Chapter 3 ).

TABLE 11

Mechanisms to embed PPI

Summary of key findings

This is one of the first studies to contribute significantly to our understanding of PPI as a concept, through the analysis of a large number of case studies, selected to capture varying levels of PPI embeddedness, in order to understand how it may change over time during the research process.

In testing whether or not topic area had an influence on the embedding of PPI, we found similarity between the nature of the clinician–patient relationship and the way PPI was enacted. This was further influenced by the topic area’s history of PPI and the tacit models that had evolved. For example, we found PPI in IDD studies to be framed by an empowerment model and resonant of the long history of partnership working between practitioners and service users. Well-established PPI structures in some topic areas such as dementia provided a pragmatic source for the lay perspective, but we found unintended outcomes for this model, including the outsourcing of PPI to external parties with little researcher engagement. It also exemplified a ‘one-off’ model whereby PPI was limited to a single task.

Researcher perceptions of what lay representatives could be expected to understand or be interested in, coupled with a lack of effort to communicate in an accessible way, sometimes led to limiting lay involvement in parts of the research process, potentially limiting impact. However, we also found in areas such as basic science and tissue banks, where PPI has traditionally been seen as having a limited role, that research teams were enabling PPI, leading to improved relevance of research priorities and questions.

While still challenging for a number of studies and funders, recruiting a diverse range of lay people was enhanced when the study setting interfaced with a diverse population. Particular PPI structures helped, including an outreach model with either a specific lay person or a co-ordinator acting as a bridge to a broader community. The quality of such connections was important to create the context for involvement. The resulting impact was culturally sensitive, participant-focused research designs.

In contrast, researchers’ descriptions of ‘usual suspects’ as lay representatives reflected a perception of concerns about the professionalisation of PPI. However, our findings suggested this was at odds with reality and with the advantages of the experienced lay representative being able to develop a number of skills that helped their role, and enabling a career trajectory for the lay person within PPI.

An important finding in both the survey and the case studies was the dual role, whereby the lay advisor was also a study participant. Although this had the benefit of real-time feedback about the impact of the research design and enhanced a sense of ownership of the study for lay respondents, there was also evidence of conflicts of interest and a blurring of roles. In some case studies the dual role was a deliberate PPI design; however, in others it clearly demonstrated that involvement was not understood as being different from participation, and highlighted the level of PPI drift away from INVOLVE definitions. It was also indicative of a lack of training or experience in PPI, particularly in novice researchers. Training or on-the-job experience not only helped researchers to differentiate between involvement and participation, but also enhanced an understanding of what both parties bought to the table. Development of positive relationships underpinned by trust was the minimal requirement for any form of PPI; this led to improved self-worth for lay people, and increased researchers’ confidence in their work. Breakdown in this relationship had a profound effect on levels of PPI embeddedness over time.

It was clear from the case studies that PPI was most likely to be embedded when hosted in well-resourced research centres with a dedicated budget and PPI co-ordinator. PPI groups and panels had continued engagement with the research host organisation, were reimbursed equitably and had social interaction with the research teams; these are crucial to the sustaining of positive relationships. Resourcing PPI in such a way also enabled a fully entwined model of PPI, in which lay people and researchers worked seamlessly together, with research priorities and research questions created by the lay people involved. This generated some research programmes that would not have been run without lay involvement. However, embedding PPI to this level required not only resources but also time to develop.

We found that funder requirements played a key role in influencing levels of reimbursement. In addition, how PPI was operationalised in individual studies could be traced back to the funder’s ethos of PPI. Within funding organisations there was a growing interest in evaluating processes and outcomes of PPI within studies. However, even with funder expectations, only a limited number of case studies were reflecting on and evaluating PPI in an ongoing way to improve the quality of PPI processes and outcomes.

Enabling contexts

The findings suggested there were eight enabling contexts for the mechanisms ( Box 5 ). Five of these (funder, topic area and design, resources, organisation of PPI and research host) were expected, based on the literature, and shaped our sampling framework to ensure a range of case studies as a test-bed. The other three (training, positive relationships and positive experience) became visible during data collection and analysis.

Enabling contexts C1 Funder requirements for PPI in research.

Context–mechanism–outcome configurations

As described in Chapter 3 , through an iterative process we tested candidate CMO configurations within each case study and discussed our findings with case study respondents in the tracking interviews, with our reference groups and finally at the four regional events. We identified six CMO configurations that explained salient case study actions, potential contexts, plausible mechanisms and potential outcomes, both intended and unintended. CMO configurations focus on immediate outcomes within a study. It was not possible to include longer-term outcomes of a study, as these evolve over a longer period of time. Tables of each CMO are presented and then illustrated by data and case study exemplars. Within exemplars, NPT radar plots will be shown, and any change in PPI embeddedness over time will be illustrated through tracking radar plots.

  • Purpose, structure and role of patient and public involvement

Table 12 illustrates the CMO configuration for this action. Funder requirements were a significant enabling context, and had resulted in a more structured approach to PPI. It was also facilitated by host organisations with an established PPI infrastructure, such as an established group or panel, and access to training. At the time of data collection, this enabling context was provided by some topic areas (dementia and diabetes mellitus) with network support for PPI. Having adequate resources to maintain this group in terms of administration and reimbursement was vital for sustained engagement with PPI in research.

TABLE 12

Context, mechanism and outcome configuration: purpose, role and structure for PPI

For some case studies, the purpose, structure and role for PPI were an inherent part of the research design. For example, CS03 (see Box 10 ) and CS23 (see Box 21 ) were funded to coproduce an intervention (self-management website and mobile phone applications for young people with diabetes mellitus). Other case studies sometimes had to craft a PPI structure from new because of the funder’s requirements.

Case study 03: diabetes mellitus Experts by experience, different levels:

Case study 23: diabetes mellitus Four YPD as advisory group.

Funder requirements

Researchers were particularly aware that when applying for specific grants there were even stronger imperatives to have PPI as a funding requirement. PPI was recognised as a part of the contemporary research landscape, and some reflected that having formalised PPI as a requirement was beneficial, as experience of good PPI usually leads to more in the future:

more researchers are willing to engage, whether that’s because they want to or whether because they have to because of the grant application, I think there’s a bit of both there, but then again, that’s fine because those that . . . engage because they have to kind of start to begin to see the worth of it anyway. CS07Res01-01

Overall, the funder respondents clearly asserted that PPI both in research and at funder and system level had developed significantly over the previous 5 years, describing a journey along a continuum of learning and understanding of PPI, despite noting that there was still some way to go until it was fully embedded as normal practice:

I think organisationally that’s been a sea-change . . . Externally with researchers I sense there has broadly been a change but there’s still a lot to do, but certainly the quality of the PPI anecdotally that we’re getting in our applications is on the up, possibly to do with . . . everything being reviewed by a public contributor. Funder01

Structures and processes for PPI within funder organisations themselves inevitably varied and strongly reflected the influence of their core funding source, mission, scale and length of service. PPI structures had developed either quite systematically or more recently and organically as part of the overall PPI movement.

Working closely with INVOLVE, two overarching programme management organisations and two research programmes that are funded by central government had, over a number of years, developed similar, embedded structures for PPI within their organisations. However, the sheer volume of applications to process could potentially result in the PPI representatives having to work with a conveyor belt approach. The industrial scale of PPI as metaphor was also picked up by one of the lay representatives:

I think, having started from a low base, it’s [PPI] now in danger I think of almost becoming an industry; that is that everybody concerned with health care has to have some public involvement, and that goes for GP practices, hospitals, and very much in research, all areas of research . . . It sometimes strikes me that it’s a kind of bandwagon. Don’t get me wrong, I think it’s one of the most useful things in the health economy, but it seems to have made jobs for an awful lot of people, let’s put it that way. Funder07(lay rep.)

The other funding bodies taking part in the RAPPORT study had only recently started to implement PPI strategies in their organisations. A government-funded research council had endorsed its PPI strategy only a year before and there was now a strategic vision around PPI. The structure of this funding organisation was less complex and was led by a member of staff responsible for both public involvement and engagement. This organisation had a PPI panel of around 20 members who were offered the opportunity to be involved in particular funded projects; alternatively, the organisation would ask specific medical charities to nominate lay representatives for particular condition-specific projects. Another large national funder, financed through endowments, had a different stance on PPI, focusing more on public engagement:

patient and public involvement doesn’t just have to be people in a focus group or a patient representative on a steering committee, it can, you can use kind of more engagement approaches that can still inform and can kind of be part of the research process . . . sometimes when I talk to people in the patient and public involvement sphere there’s quite a narrow definition of how they see patient and public involvement, and so yeah, I can see it a bit wider than that. Funder08

Public engagement was seen as a key policy driver within this organisation, and strategically it focused on facilitating research teams to improve its public engagement, with PPI being seen as operationalised at research team level.

We also interviewed two representatives from condition-specific medical research charities. Their PPI strategies had gradually developed over recent years:

we’re currently looking at expanding it, so it is something that’s definitely on the radar of people within the charity, it’s just the technicalities. I think, you know, everyone’s definitely willing to do it and I know that our Medical Director is very keen on PPI, and I think it is almost evolving organically . . . Funder01(CharityA)

A major finding from the interviews with funder representatives was that their stances or values (and thus PPI structures and processes) were actively shaped by the origin of their funding and their histories. The funding organisations that received government public funding as part of a national research agenda clearly articulated the reasons for PPI in methodological terms:

It [PPI], you know, is likely to improve recruitment. It makes sure that it meets patient needs so that when it gets out the other end if you like into the implementation phase that it can actually have a possibility of having impact on an individual with a said condition. Funder04

In contrast, the medical charities reliant on fundraising spoke of PPI in terms of an ethical rationale:

we get our money from the public, from people with the condition, so it’s really important that we include viewpoints of people with the condition in our decision. Funder02(CharityB)

Hence, funders influenced PPI in subtly different ways depending on their organisational values. Case studies funded by NIHR funding streams were required to have PPI as a different way of working within the actual research process because of the emphasis on the methodological importance of PPI. In contrast, those funded by charities tended to have less focus on a requirement for PPI in the actual research process, with structures in their organisation concentrated more on ensuring PPI in funding decisions.

Structures for patient and public involvement

Host organisations, and in particular CLAHRCs, were instrumental in providing a PPI infrastructure. This often involved having a designated lead for PPI. Six of the case studies had a dedicated PPI co-ordinator who was separate from the research team, and a further case study had a research team member who took on the role of the PPI co-ordinator as part of their duties. Case study 21 ( Box 6 ) had a colocated co-ordinator who, as a non-researcher, was seen to bridge the gap between researchers and the public:

Case study 21: IDDs The research centre hosts a large PPI group made up of parents.

she’s become a great interface between us and the families because she helps, she’s . . . she knows enough about research to be able to explain what we do, but equally doesn’t know enough that she can challenge me or others in the team to explain more clearly what we’re asking of families. And I think that’s probably the greatest reason for our success has been the sort of creation of that role and the development of it. CS21Res01-01

Case study 21 exemplified fully embedded PPI which was enabled by all eight identified contexts. It also demonstrated an ‘entwined’ model of PPI in which research and PPI were wrapped together much like a double helix. It was hosted within a research centre primarily funded by a charity (C1) with a topic area (children with severe cognitive disabilities) (C3) where active involvement of parents was seen as a prerequisite of meaningful research. The study design (systematic review) (C3), compared with the ongoing qualitative research being undertaken in the programme of work, required more effort from the research team to ensure that parents were involved and the review was rigorous. The research centre (C7) had an established PPI system (C6) including a funded co-ordinator who supported parents and undertook extensive outreach work. The centre was also part of a CLAHRC with a vibrant PPI community and resources for PPI (C4), and parents were reimbursed for their time and received training (C2) for their role. Resources also included the time researchers needed to work with parents on the systematic review. This level of resources was necessary for an entwined model of PPI (see Chapter 7 ). There was a strong focus on positive relationships (C5) that were developed over time and enhanced by social activities. This led to a positive experience of PPI (C8) for all involved and the sustaining of a virtuous cycle whereby PPI became increasingly embedded. At the start of data collection PPI was already embedded in CS21, so there was no change in the tracking radar plots over time.

The need for time to develop a PPI infrastructure that could support embedded PPI was also clear in CS22 ( Box 7 ). The topic area of CF had little history of established PPI structures, and the study designs are more commonly towards basic science. This case study captured the early days of study set-up and developing PPI, so radar plots were less full. After a year and despite focused work by a PPI champion, the radar plots remained unchanged, suggesting that embedding PPI requires a significant amount of time: at least 5 years. The limited impact of PPI may reflect the very early stages of a research study; however, as other case studies show significant impact in the early stages of the research cycle, it may also be indicative of a neophyte PPI structure which is not enabling a fuller impact.

Case study 22: CF Parents of children with CF (one member of charity). Experience of committees.

Outsourcing patient and public involvement

For case studies not hosted by organisations with existing PPI structures, an alternative was to recruit an ad hoc, project-specific group of people or individuals to support the study as PPI. However, another possibility was for research teams to access external PPI groups or panels. Topic area (C3) was an enabling factor and respondents from two national networks covering dementia and diabetes mellitus both held a list of names of interested PPI representatives. One network had a formal registration process on its website (which was updated annually and had around 3000 names) and the other spoke of a more informal, dynamic list based on personal relationships. Both networks had ready access to around 150–250 regularly involved and engaged PPI representatives; had been approached by researchers (in this topic area and beyond) for PPI in protocol development, funding before the application stage, help with PPI budgets and recruitment; and often organised local focus groups to gather PPI views.

Panels were preferred by some because they were more focused on a specific question and were hoped to consult with a wider population:

I think that the PPI, you get from a reference panel is potentially more focused on specific important questions . . . for example a Trial Steering Committee which might only meet twice a year or, and if the layperson can’t attend. ResearchNetwork02

Panels were felt to be a very effective way of using PPI time and skills, and easy access to existing groups made PPI feasible within the time line of a project. However, although convenient, recruiting solely through local PPI networks with trained and prepared members of the public was seen as not always appropriate for effective PPI. Researchers within some of our case studies expressed concern about the difficulty of recruiting more than just the ‘usual suspects’:

one of the problems is ensuring that you actually are getting real and representative user involvement and not just the people who happen to be around who always get signed up to these user involvement things . . . actually it’s quite easy I think to get the usual suspects. CS23Res04-01

There was also evidence that relying on an external group had led to a ‘one-off’ model of PPI in which researchers had requested help for just one task and there was an absence of PPI throughout the rest of the research process. This limited the potential impact of PPI and was characterised by a more ambivalent view towards the value or impact of PPI. In a few case studies, the CI appeared unconvinced of the value of PPI:

but where’s the evidence that it [PPI] does work, maybe there’s scientific management for a programme that should just be done by scientists, internal, external and managers and maybe there are other elements that really need a PPI input, I don’t think that’s terribly well worked out at the moment. CS01Res02-01

Case study 01 ( Box 8 ) provides an example of this model.

Case study 01: dementia Panel: an established local research network panel with a paid co-ordinator, who has worked with CI before. Panel asked for views on access to patient notes.

The evidence suggested that training around PPI for researchers was likely to be an enabling context, but there were mixed and even polarised views on training for lay representatives. Nevertheless, even in case studies with embedded PPI, researchers had not received formal training on PPI. Rather, they had learned through experience within an environment supportive of PPI.

Understanding PPI as different from study participation was a prerequisite for the development of appropriate structures, purposes and roles for PPI. Most researchers could articulate the difference; however, it was significant that many junior researchers could not. This lack of understanding was attributed by some to a lack of formal training:

there was no formal training, I just, you know, from what my colleagues and supervisors have just briefly mentioned but nothing formal on it and I think it would be an important part early on for trainees interested in research. CS14Res02-01

Of those lay respondents in the case studies who had received training, the majority had been provided by CLAHRCs, public involvement groups or research networks. However, the need for training for lay representatives did not emerge so strongly from the data as for early-career researchers. Indeed, various arguments were put forward against training, such as potentially compromising the lay perspective, or skills already existing because of extensive PPI experience or transferable skills from work life:

I don’t think there was any necessity for training at all. There’s certainly obviously one or two people have got good committee experience who are sitting round the table, on the lay side, so no, I don’t think there was any necessity at all. CS13PPI05-01

In stark contrast a minority of lay representatives suggested it was impossible to contribute meaningfully without some understanding of research:

I don’t think that you can just so easily shove inexperienced patients in to a PPI role without them being, having some training and having some support because there’s no question that, you know, the whole research agenda is incredibly complicated and they talk in a language which is, you know, if you’re not a researcher you sometimes have no idea what they are talking about when they’re talking about face validity and constructs and confidence intervals and so on and so on. CS14PPI02-01

However, the above quote suggests that this lay representative felt it was essential for the PPI representative to be able to cope with the research world, rather than the research community needing to make the effort to include the lay world in an accessible way. Making the effort also included working towards recruiting lay representatives who reflected the diversity of a study population.

  • Recruiting lay representatives reflecting the diversity of a study population

Table 13 illustrates the CMO configuration for this action. Formal training for researchers played a part in helping them to identify the need for this action, but experience on the job of recruiting diverse lay representatives was a more common enabling factor. It was easier to achieve this action when the research setting interfaced with and had access to a diverse population. Particular topic areas such as IDD had developed links with less-heard groups, and in a number of case studies these links were provided by a PPI co-ordinator or a lay person within an outreach model. In a few case studies, recruiting lay members as representative of the study population was actually operationalised through recruiting study participants to also have advisory input: a dual role.

TABLE 13

Context, mechanism and outcome configuration: diversity

Strategies for recruiting lay representatives

Being able to understand the research through the viewpoint of a target population was seen as key:

I was sat on a table with speech and language therapist, physiotherapists, paediatricians, and a handful of parents, all as equals, you know? . . . and I was just thinking ‘What does that mean to me as a parent’, thinking of my child’s capabilities and all the other children that I knew. CS21PPI01-01

However, finding lay representatives who they felt could present the viewpoint of the research study’s target population was often challenging for research teams. This was more frequently cited for BME groups. We attempted to include case studies that were likely to have a target population from the BME community. One case study specifically focused on the experiences of a particular ethnic group living with arthritis (CS18). One of the study sites was located in an area with a high percentage of people from this ethnic background, and the lay representative was recruited through that site:

I was going to the clinic, attending the clinic and the nurse actually asked me if it’s okay because I speak different, three or four different languages. CS18PPI02-01

This opportunistic recruitment meant that CS18 benefited from the input of a lay representative who demonstrably understood the enablers of recruitment in far more depth than the research team:

what we had was an audio CD because a lot of people do not read the script, [specific language], so some of our interviewees did not speak English so we got the information sheet translated and put onto CD and she [PPI01] listened to that and gave feedback on that because there are different dialects of [specific language], apparently some are deemed posher than others and there’s all sorts of things that I was not aware of initially. CS18Res01-01

While there was trust in this lay representative’s expertise demonstrated by the peak in the collective action segment of the radar plot (bold outline) ( Box 9 ), the construct as a whole was affected by one major challenge: that the CI (who was effectively the PPI lead within this study) and the PPI representative were located at a significant distance from each other.

Case study 18: arthritis Patient and public involvement representatives normally recruited to each study via an established PPI group based at the university. Only one took part in CS18. Expert by experience (has condition). This PPI representative was (more...)

We also included four case studies focused on type 2 diabetes mellitus with the expectation that these would include a relatively high percentage of research participants from BME groups susceptible to this condition. One of these case studies (CS03) ( Box 10 ) had used strategies (advertising and interviewing applicants) to recruit a diverse range of lay representatives:

Strategies used when recruiting individual PPI representatives reflected researchers’ attempts to involve people who could bring both specific and broader perspectives. Recruitment of individual lay representatives was from five main groups: general public; expert by experience; carer/parent; patient representative; study participant. Individuals could take on multiple roles and represent their views at different levels. However, relying on just one or two individuals also raised the issue of representativeness:

it’s impossible, you can’t expect one person to speak on behalf of everyone so I guess the question would be what would be useful, or truly influential patient involvement? Is it enough to have just one person or two people who will be very, very good and who will be enthusiastic, but the question is, how representative are their opinions into their input? CS03Res02-01

Nevertheless, one model of using a single lay representative as a conduit to a broader constituency appeared to work well. The outreach model, as exemplified by CS02 ( Box 11 ), involved one representative from a charity who then linked with 20 members of the support group in an iterative way to inform the study design and recruitment materials. An unforeseen impact from this PPI was to raise concerns over the safety of the study, resulting in extra study visits and a questionnaire (see Impact and outcomes of patient and public involvement ).

Case study 02: diabetes mellitus Steering committee: national representative. One PPI representative (senior position in charity) sits on trial steering committee. PPI representative then consults the (20) panel members, invites feedback, collates answers (more...)

Some case studies also bought together project-specific panels. Case study 12 ( Box 12 ) was particularly enabled by being located in a teaching hospital with relatively good resources for research (C4), which were sufficient for PPI honoraria.

Case study 12: diabetes mellitus Newly formed panel: experts by experience, participants on the trial, mentors on the trial. Less PPI at the early stages of the research, became involved with study documents. One lay representative had already worked (more...)

Challenges in ensuring diversity

Researchers acknowledged there was much work to be done to ensure diversity in PPI. The fact that only a very few of our PPI respondents were not from a white British background exemplifies the common problem as described by one of the funders:

we have as much of a problem as anyone about, you know, diversity and all those issues are still issues which we need to explore further. I think often public, people who get involved with PPI are a self-selecting group and it’s really difficult to bring in groups wider and that’s a usual excuse and I hate it, and I hate it when researchers say it. But I, it, you know, for example if somebody couldn’t read and write how would we include them in this process? If someone wasn’t, we do manage to include people who are not computer literate but then these days how are they going to even find out about us if they don’t have a computer? How are they going to know who to ring? Funder01

Difficulties in accessing ‘representative’ PPI were particularly marked for public health studies when the focus was on healthy or ‘at-risk’ populations with particular lifestyles. The difficulties for public health studies was also linked to the setting (e.g. broad communities) in which they took place. Those studies taking place in settings with ready access to patients obviously had greater potential for recruiting both participants and PPI representatives onto their studies:

the problem at the university is that those researchers that aren’t clinical or don’t have good links into the clinical setting, it becomes very difficult to identify service users to sit on a panel like that so we’re in quite a privileged position because we’re right next to the outpatients clinic and that makes our life a lot easier for maintaining that model. CS18Res01-01

The dual role

Clinicians who were also researchers had the added advantage of having ready access to patients as potential PPI representatives. For example, one case study (CS14) (see Box 26 ) hosted by a district general hospital with few embedded PPI structures was able to involve patients through an active condition-specific support group facilitated by clinical department staff. However, the distinction between being involved and being a research participant was often blurred in this case study, with PPI being understood by many of the respondents as a dual role. This dual role was overt in another arthritis-related study (CS08) ( Box 13 ), where the PPI respondent was also a study participant. While there are potential ethical conflicts here, this lay representative actively recruited participants through her own network and had a strong sense of purpose. This action-orientated approach to PPI resulted in a fuller quadrant in the radar plot denoting a positive appraisal of the PPI within CS08 (see bold outline in box figure).

Case study 14: arthritis Hybrid: national representative, local service user group and expert by experience. However, these components did not come together and hence there was no cross-fertilisation. The national representative has advised nationally (more...)

Case study 08: arthritis Dual role: PPI representative already known to CI through being on funding committee but also has joint issues so is participating in the research as well as acting as an advisor.

Although respondents in CS08 were comfortable with this dual role, it was operationalised in an ad hoc manner that was unlikely to lead to any embedding of PPI. In contrast, this dual role was carefully constructed and managed in a longitudinal cohort study (CS13, see Box 16 ). A rolling PPI panel was drawn from study participants and the role was clearly defined and separated. The impact of this role included both increased public engagement with the study and improved participant retention. This model of PPI was enabled by topic area (public health with healthy participants) and the longitudinal design, which allowed relationships to be developed and sustained over time. This was a well-resourced study with dedicated PPI staff and good organisation, and was run from community hospitals at the heart of local populations. For the public undertaking this dual role, there was a sense of ownership of the study, with subsequent sustained engagement. Two tissue bank studies also had lay representatives who advised but also had donated samples. In CS17 (see Box 23 ), engagement was sustained, but for the other (CS16, see Box 20 ) the sense of ownership became a cause of conflict, which is presented in Enablers and barriers to trust .

Case study 13: public health ‘Consultation’ panel hybrid model, built upon earlier, less formalised (mass consultation, participant feedback) PPI panel drawn from large cohort study (now mostly retirement age). Panel meet quarterly with (more...)

Case study 17: diabetes mellitus Established panel for over 10 years; about 30 on panel and two attend each monthly meeting (usually invite four). Meeting and reviewing papers. PPI mixture of research-naive and ‘professional lay people’. (more...)

Case study 16: diabetes mellitus National expert network: charity. Dual role (participants and representatives).

If this dual role was to have a positive impact, then the purpose, structure and clear role boundaries needed to be defined.

  • Whole research team is engaged with patient and public involvement

A distinct action of case studies where PPI was embedded was engagement of the whole team with PPI, and having the skill set to do this. Funder requirements (C1) for plain English summaries were bringing into sharp focus the need to be able to explain technical aspects of the research in an accessible way, and the most effective way of doing this was to work in partnership with lay representatives (C5). This needed time to achieve (C4) and could also be helped through specific training (C2). It was particularly evident as an action in the IDD topic area (C3). The CMO configuration for this action is shown in Table 14 .

TABLE 14

Context, mechanism and outcome configuration: whole research team engagement

Relying on one person to lead patient and public involvement

As described in Purpose, structure and role of patient and public involvement , having someone to lead and co-ordinate was important in embedding PPI. If there was not a designated co-ordinator, this role was often carried out in addition to a junior researcher role and was not part of the original job description. Different levels of commitment to this role were found and PPI representatives spoke of often not having one ‘designated person’. Continuity of personnel with responsibility for PPI was an issue. For example, one PPI representative reported seeing someone different at each meeting (CS05) ( Box 14 ) and another said the enthusiastic support ‘gradually dwindled’ (CS14). If the whole team was not engaged with PPI, the loss of the PPI champion had a detrimental impact.

Case study 05: arthritis Steering committee: one expert by experience, recruited through national arthritis body, who was a patient of the CI. Was asked to change consultants. Nursing background and interested in research. Understands some of the medical (more...)

Patient and public involvement as a collective action

Case studies demonstrating agreement of all individuals in the team that PPI should be part of their work were particularly strong within the IDD topic area, where there is an acknowledged history and strong investment in PPI. The CI from CS11 ( Box 15 ) clearly articulated this:

Case study 11: IDD Two PPI representatives are new to PPI in research (one voluntary worker, one carer) and one more experienced (expert patient). Preference for PPI recruitment from established condition-specific networks (built on previous relationships (more...)

in order to understand and develop theory effectively, you need to really have a conversation with service users and probably somebody who has the problem with the condition, and that is how psychological theory develops. You know, it is that, ‘Are you doing something to people or are you doing it with people?’ and doing it to people, you know, there’s such a power imbalance, and given the backdrop and the history associated with people with disabilities internationally, that’s not politically palatable to me personally and to, you know, society, I suppose. CS11Res01

Although the NIHR funding (C1) was used to pay out-of-pocket expenses, this case study was hosted by a medical school, with the CI reporting limited engagement with PPI. However, it is the topic area (C3) that is the strongest enabling feature, suggesting a culture where ‘nothing about me without me’ shaped research practice. This CI also framed the challenge to explain technicalities more clearly to lay audiences positively, as good practice for communicating ideas to the public:

saying things like, ‘Oh, this is a stepped wedge design,’ and ‘We’re randomising,’ . . . you can use that language, but people aren’t going to understand it. So, you’re going to spend all your time explaining what you mean, so you might as well just use simpler language to start with, and perhaps really as a researcher or scientist, that’s a good thing because it helps improve your communication skills with lay people and the general public. CS11Res01-01

This whole team engagement was not unique to IDD as a topic area. For example, in CS13 (public health) ( Box 16 ) although a project-specific PPI panel was facilitated by a lead person, all senior researchers took it in turns to attend panel meetings. The embedding of PPI in this study was enabled through access to resources from grant monies (C4) and a longitudinal design (C3) that enabled relationships to be sustained (C5).

  • Mutual understanding and trust

While formal training (C2) had a part to play in helping both researchers and the public to understand each other’s roles in research, positive relationships (C5) sustained over time led to PPI as a positive experience (C8) and the development of trust, which was key for this action. Reimbursement of out-of-pocket expenses and time contributed to maintaining trust. If clearly articulated, funders’ expectations (C1) of reimbursement were an enabling context, as was the topic area (C3) if reimbursement was normal practice. Host organisations (C7) had a key role in providing resources (C4) for reimbursement and ensuring payment was smooth. The CMO configuration for this action is shown in Table 15 .

TABLE 15

Context, mechanism and outcome configuration: mutual understanding and trust

Coherence in understanding the contribution of patient and public involvement

As the bedrock for trust, lay representatives and researchers needed to have a shared understanding of the purpose of PPI. Novice researchers were more likely to be unable to fully distinguish PPI as separate from research participation. For example, a registrar in CS14 defined PPI as:

patients contributing to research and enrolling into research studies, whether they had portfolio status or not. CS14Res02-01

While this impeded an understanding of what PPI could offer to the research process, other researchers and PPI representatives provided a variety of reasons for carrying out PPI including gaining insight into the lived experience of a particular health condition, and to provide reassurance for researchers that their research question resonates with the patient community. This was exemplified in CS07 ( Box 17 ).

Case study 07: diabetes mellitus Experts by experience panel (≥ 10 patients who have lived with diabetes mellitus for over 5 years). Recruited from diabetes research network panel. Members of the CS07 panel are on their own Diabetes UK (more...)

Case study 07 was enabled through an established diabetes (C3) network group (C6) housed in the host organisation (C7). The study focus on processes of care (C3) also enabled coherence. PPI members met regularly and were involved in a number of projects which helped promote sustained engagement (C5). However, lay representatives were not reimbursed for their time because of bureaucratic difficulties; rather, they were taken out for a social meal.

Whereas the experience of established panels was seen by many researchers as a bonus, others spoke of the tension between wanting someone who was ‘outside’ the research environment and wanting someone who was also able to engage with research studies (possessing some research skills) and thus perceived as being able to perform the necessary PPI tasks. This notion of wanting the right person with a short distance between direct experience and its interpretation but who also can feel comfortable in a research environment is maybe a contradiction in itself. There was evidence of an ongoing debate about whether or not the experience of a condition (direct or indirect) was seen as less legitimate because of that person’s professional background, experience or training in research or health care:

we’re all patients . . . yeah, and some of us have PhDs and some of us don’t, so it’s quite difficult to kind of define what is a lay representative . . . they’re really just people who, actually, through their qualifications, they should be research assistants but don’t happen to have a job in research but are on a lay panel. And I kind of think ‘what . . . are you really a lay person? You’re just an unpaid researcher’, but I’m not entirely sure whether that’s right . . . CS17Res01-01

Our findings suggested that defining PPI as a discrete and commonly understood component of research was difficult but the range of PPI representatives can be summarised through a fourfold typology based on an insider/outsider perspective (on one axis) and a range of research skills (on the other) ( Figure 8 ). Research studies can be placed along these axes; however, within one research study there may be a mixture of individuals with varying skills and perspectives.

Insider/outsider perspective.

While the insider/outsider debate was articulated in a number of case studies, those that had embedded PPI were likely to have sustained engagement with the same group of PPI representatives over a long time.

Building relationships over time

We found that the relationship between the researchers and PPI representatives was a key factor for successful PPI. Relationships took time to establish, which was particularly difficult at the beginning of research (or even before the proposal is written). One finding from the case studies was that the majority of PPI representatives had a previous working relationship with the research team. Of the 51 PPI representatives, 33 (64.7%) had some prior working relationship with either the CI or members of the research team (three were patients of the CI and also members of a service user group, so had worked together before), nine (17.6%) had a more distant acquaintance (but described themselves as being within the same loose network) and nine (17.6%) PPI representatives were completely new to the research team (recruited from outside existing structures). The obvious advantage of having a previous relationship meant that PPI could start as soon as possible within the research project, whereas more time was needed to establish relationships through informal small meetings if the lay representatives and researchers had not previously met.

Research teams spoke of initial meetings where everyone got to know each other and having these times of informality before starting on the ‘academic’ business. The benefits of PPI representatives having the opportunity to get to know each other also provided support later in the project. Social elements were important in encouraging and maintaining continual engagement in the research study and should not be underestimated by researchers. Some of the case studies also ran social events outside the research, which again helped to build and maintain relationships:

We do these family fun days as well, which we get together once a year, just to get together at the zoo or something. [PPI co-ordinator] works phenomenally hard to build relationships with the families that . . . So, it’s a partnership really. CS21Res01-01

In more formal advisory or steering committee meetings, PPI representatives spoke of being specifically welcomed into the meeting (sometimes being met beforehand). Most importantly, during the meeting, successful PPI was being ‘genuinely’ listened to and their comments taken on board. The relationship between the researchers and the PPI representatives was key to fully embedding PPI within the research study. The researchers needed certain social skills, which included being approachable, good listening skills and group work skills:

initially facilitating and always presented a positive, welcoming, friendly, supportive space to you. CS17PPI01-02

Patient and public involvement representatives reported that meetings needed to have a ‘flat structure’ where PPI representatives felt free and at ease to speak.

Relationships could change over time, either through loss of trust or as trust developed, as illustrated in CS19 ( Box 18 ). Although only subtly different, the radar plots show a change in all quadrants but particularly in collective action (bold box), where M10 (trust in each other’s PPI work and expertise is maintained) is included as a mechanism. This reflects clarification of roles and the improving relationship and trust in the PPI work:

Case study 19: public health Committees: two representatives (one a coapplicant) on trial steering committee (meet twice a year). Two PPI representatives on trial management group (meet once/twice a year).

I don’t know what they want me to prepare for, I don’t know what they want me to do, and I don’t know if the confusion is because of my professional role [. . .] and I don’t know if they’re waiting for me to take the lead, and I’m waiting for them to treat me as a patient. . . . I’m a little bit disappointed. It feels almost tokenistic. CS19PPI02-01
Conflict between roles resolved . . . CS19PPI02 feels happier now that they are no longer post-surgery, less vulnerable. They had a long chat with a rheumatology person in department who had done a lot of PPI work who reassured CS19PPI02 that one PPI voice is better than none, more confidence to feel you don’t have to represent all patients, can just give your own experience. Different way of looking at the value of their contribution. CS19PPI02, notes of tracking interview 6 months later

Trust as the foundation for patient and public involvement

A relationship framed by trust was the minimum requirement for PPI to have a positive impact. Although PPI was not embedded within CS14 (see Box 26 ), the relationship between lay representatives and the clinician was based on trust built up from a clinician–patient relationship with continuity over time:

there’s a trust there, I trust them that they wouldn’t ask me to do something that wouldn’t be, you know, it would be difficult or wouldn’t necessarily be appropriate or whatever. CS14PPI01-01

Some researchers also trusted their lay representatives to undertake the work in a way that was workable for the researcher:

It’s always good, you know, on research it’s you need good people you can work with and that’s what I would be looking for, to set up some relationship of trust and mutual respect . . . Without thinking of them as a hindrance. CS15Res03-01

Case study 15 ( Box 19 ) exemplified how, even when resources were minimal for PPI, the very existence of mutual trust resulted in positive PPI impact. This study was housed in an organisation with no PPI infrastructure and with minimal resources for PPI despite the study being funded by the NIHR. The research setting [intensive care unit (ICU)] provided particular challenges: consent and recruitment difficulties in a high-stress environment; difficulty in recruiting lay representatives, as they were often traumatised by their time in ICU; and lack of resources, as there was no large charitable funder. The lay representative in CS15 had an impact on recruitment processes for the study and provided a valid argument to present to the ethics committee for this approach:

Case study 15: dementia One national representative. PPI role confined to trial steering group.

we put a thing here saying in the consent ‘to continue information now you’ve regained consciousness, we would like your permission to continue in the research’, now [PPI01 has] written ‘I realise this might not be possible but in my own experience of delirium I was regarded as having capacity long before I was in my right mind or capable of rational decision making. I appreciate this may be beyond the scope of the study but if there were any way to change the emphasis for the patient remaining in the study unless they chose to opt out, I think that would be much better’. CS15Res03-01

It can be clearly seen how M10 appears as a peak in the collective action section of the radar plot (bold square).

Enablers and barriers to trust

Sustained feedback to PPI representatives was a clear enabler of trust and continued engagement:

and they’re always thanking us for our participation. All the time. Always saying, you know, I get it in e-mail messages, we get it at the meetings and they always say how valuable our input is, you know, they make us feel worthwhile and that is good. CS13PPI03-04

This feedback was recognised by many researchers as being important:

I think it’s important, what I’ve learnt is that if you are going to ask them things you need to feed back to them so that it’s terrible to actually ask their opinion and they never hear again, so I’m quite good now, it’s an agenda item that you know, I feed back what I’ve heard from different people, because they’re left wondering . . . CS07Res01-01

The forum in which researchers and lay representatives came together was also an important enabling context for trust. The majority of our case studies had PPI representatives as members of steering committees (one or more lay representatives per study) which met every 3 or 6 months to advise the research team but did not necessarily have a ‘hands-on’ role with the research. However, different research teams made different uses of their steering committee members, with some members making comments only during the meeting and others who were asked to comment on documents throughout the study. As shown in CS04 (see Box 22 ), there was a varying sense of equality within the committee:

Case study 04: diabetes mellitus Experts by experience.

it wasn’t run by the Professor from the top down in sort of military fashion, it was a round table discussion where anybody could contribute . . . whilst it could have been intimidating actually it was very welcoming, and the person who chaired the meeting was very sensitive to that. CS04PPI02-01

However, the formal term ‘steering committee’ put some PPI representatives off: ‘if they said someone to be on the Steering Group I mean I would never, I would have just thought well that wouldn’t be . . . that sounds too high powered for me’ (CS04PPI01-01).

Despite it often being seen as good practice, there was little evidence that this relational integration was being formalised through job descriptions or contracts for the PPI representatives. However, at the start of the study researchers often clarified expected commitments to attending meetings; other PPI input was often less formalised. Those case studies which had high levels of PPI activity could achieve this through flexibility and allowing PPI representatives to ‘dip in and out’ as their other commitments also varied:

parents will stick with the programme because they know that they can step in and out if needs be, and the team also think about how they can include people that might not be able to travel, so whether it’s joining in a meeting by phoning in to it and participating over the phone or sending responses or comments and feedback in an e-mail, so it’s made it available and it’s made accessible. CS21PPI02-01

However, trust in CS16 ( Box 20 ) was lost because of a lack of formal agreements about access and ownership of a database. This issue appeared midway through data collection and the impact can be quite clearly seen on the radar plots tracked over time. The impact can also be seen in the way the PPI was appraised (hatched box); because of this experience the charity would get legal documents drawn up before working with researchers again.

Virtual patient and public involvement

There has been a recent move towards the increasing use of technology and teleconferences being used as a means to include lay representatives who might otherwise not be able to attend meetings. However, this move towards ‘virtual’ contact as opposed to ‘face to face’ has implications for the establishment of relationships. One lay representative said that they always wanted an initial face-to-face meeting to make any following (virtual) meetings easier. As presented in Strategies for recruiting lay representatives , being unable to meet in person also caused problems in CS18, where the CI and lay representative were in different regions. The challenges of building and sustaining relationships through virtual contact were also raised by a funder. Maintaining arm’s length relationships was acknowledged to be difficult for the army of remote lay reviewers, and they found it difficult to sustain any more active involvement. Case study 23 ( Box 21 ) provided an example of virtual PPI with young adults, and also demonstrated how this medium provided an outreach model (see Discussion ).

The benefit of this virtual form of PPI was obvious:

I’ve got a main informant on Twitter . . . asked her if she could work with me on developing a paper and she’s a young person . . . and so she basically threw some question out to Twitter to her one and a half thousand followers . . . and we sort of put some questions to them and we’d written a paper within 3 weeks. CS23Res04-01

Case study 23 also had an advisory PPI group made up of four young people with the condition. At their request, this group was hosted separately from the research team meetings and deliberately had an ‘informal feel’. These separate meetings were envisaged to be a series of evening, face-to-face meetings with monies allocated to cover travel expenses. However, in reality, as a result of competing demands placed on the attention of this age group, the group did PPI ‘virtually’. Co-ordinating such involvement was a significant workload, which was difficult to predict and cost for. However, as this was adapted to over time, the tracking radar plot became fuller.

Reimbursement

Reimbursing lay representatives for their time is intuitively an enabler of trust and seen as normal good practice, yet payment for time was surprisingly rare in the case studies, although all were paid for out-of-pocket expenses. This was not only because of financial restraints but also reflected a continuing debate from a minority of respondents on how payment fitted with the notion of volunteerism. For example, in CS08 (see Box 13 ) PPI was felt to be more of a voluntary role, which payment would then ‘professionalise’:

No, I think it should be voluntary . . . because you’ll be paying for services for like, I guess, advice or public feedback, if you’re paying them then it’s, I don’t think, it’s more official, I guess . . . CS08Res02-01

This was rejected by many lay representatives:

It is and part of the problem is that people just kind of make an assumption, oh they’re patients, we won’t need to pay them. And you know our time in our life is just as . . . important as a researcher’s or a doctor’s. CS14PPI02-01

Among the five case studies reimbursing for time, the amounts ranged from £25 per meeting to £75. This was often enabled by the host organisation, such as a CLAHRC or research centre. However, even within well-funded host organisations such as HEIs, researchers related institutional barriers to paying lay representatives within institutional systems reliant upon inappropriate standardised status classifications (such as lay people having to be classed as visiting lecturers), electronic forms and difficulties dealing with cash refunds, as well as payments affecting lay volunteers’ benefit payments and tax arrangements. Hence, the host organisations that managed reimbursement and arrangements seamlessly made lay representatives feel a collegial partner with the organisation.

National charity representatives reported that they were being asked to be involved with an increasing number of research studies, which is not necessarily the main part of their work. One PPI representative called for there to be some recognition of cost to the organisation and the consequences:

there must be other charities like me in other therapeutic areas who are getting the same issues . . . So I would have thought that we should be looking at this at a national level to say if patients are going to be involved in research in a way that they have not been previously then they need support to do that and it should not, all of the cost of doing that, should not fall solely on the third sector. We should be getting some kind of NHS/government DH [Department of Health] support for this. CS14PPI02-01

One paid charity representative said her workload was such that she did PPI work in her own time. Perhaps in acknowledgement of this, another charity representative in a PPI role was contracted (part time) by the research project – yet further blurring the lines between PPI and researcher. It could also be argued that paid employment also introduces different obligations and commitments to involvement, although it has the potential to clarify an otherwise open-ended commitment.

  • Opportunities for patient and public involvement throughout the research process

A characteristic of studies with fully embedded PPI was that opportunities for PPI in all parts of the research process were fully exploited. The CMO configuration for this action is shown in Table 16 . As an enabling context for embeddedness, it was not necessarily how the PPI was organised but how much PPI representatives were encouraged to be involved and were exposed to different areas of the study throughout its stages where they could have an impact. There were reservations from some researchers on the potential for PPI in the early work of basic science designs (C3). However, we found that, with appropriate training (C2) and experience, lay representatives were effectively contributing to funding decisions for basic science studies, and prioritisation for tissue bank studies. This was further enabled by having a pool of lay representatives (C6) with sufficient interest and expertise to contribute effectively at all stages of the research.

TABLE 16

Context, mechanism and outcome configuration: opportunities for patient and public involvement throughout the research process

Patient and public involvement and the research cycle

Performing the necessary tasks for PPI appeared limited to certain stages of the research cycle. Some researchers recognised the importance of having PPI before studies were funded but acknowledged the difficulty of finding appropriate PPI representatives in a short time frame. Many researchers felt comfortable involving PPI representatives in the general review of study documents but not so certain about involvement in other parts of the research process. In most case studies there was significant PPI during study set-up, but this often decreased as the research progressed, for example when patient recruitment or data collection started. Researchers often reported that the pressure to recruit research participants (during data collection) resulted in less capacity to enable involvement of PPI representatives. This impacted most on relational aspects, with changes evident in this sector of the NPT radar plots.

The distinctive characteristic of case studies that enabled involvement at all stages of the research process was the presence of a dedicated individual facilitating PPI (e.g. CS21, see Box 6 ). A complementary or alternative approach was having a lay coapplicant who was fully involved from the inception of the design, and sometimes undertook an outreach role, or worked as an integral part of the research team. Case study 04 ( Box 22 ) had one experienced lay member as coapplicant; this was enabled by the research topic being focused on a patient evaluation tool, and by having an established PPI group with experienced lay members.

Patient and public involvement in different research designs

Funders and some researchers espoused stereotypical assumptions about the limitations of PPI in certain research designs, such as basic science, which has traditionally been an area with little PPI. A PPI co-ordinator working in a medical setting and talking about CTIMP (clinical trial of an investigational medicinal product) research observed that, because some researchers believed patients have difficulty in understanding the science and bench side of research, they find it hard to engage and have meaningful PPI. Similarly, one funder suggested PPI was more compatible with applied science:

I think it comes down to the complexity of science and the type of research that you’re talking about, some studies: when it’s very kind of lab based and it’s very molecular, doesn’t really lend itself to being able to involve the public or patient, you know, at a very kind of technical level. But there are a lot of opportunities in medical research where it is viable and it is possible to do it. Funder03

Other researchers also felt that involving PPI representatives in ‘technical’ discussions about certain research designs was tokenistic, as they were able to contribute very little:

I mean we’re doing a review of reviews . . . so it’s methodologically very challenging, it’s conceptually quite challenging, half the academics feel out of their depth, intellectually and conceptually. The PPI feel . . . that’s not to denigrate them or to put them down in any way at all, it’s not what PPI is about, . . . No, they come to the steering group and then they feel a bit left out and I think it’s a shame, I think it’s, you know I think it’s disrespectful in a way that not having, I mean I think, for that project it would be more respectful not to have PPI, does that make sense? CS03Res04-01

There was also some evidence that researchers felt concerned that some PPI representatives who lacked scientific understanding could jeopardise a study at the design stage. However, another funder challenged assumptions about the ability of experienced PPI to review less applied, more basic science applications:

when we set up these committees, there was a fear or a worry that they would have trouble reviewing basic science applications and therefore they would be more drawn towards the clinical ones, but actually what happens is, it’s quite funny really, it’s almost the other way round. I think they can see the pipedream or the hope at the end, and almost they’re more critical about clinical studies, I think maybe because it’s closer to the patient benefit. Funder01

Indeed CS17 ( Box 23 ) successfully involved PPI in approving bench research proposals in genetic epidemiology through a panel model whereby the PPI representatives are presented with lay protocols written specifically for the panel.

  • Levels of involvement

Beyond stages of research, respondents identified themselves as working at different ‘levels’ or degrees of consultation and collaboration. Rather than being polarised, these approaches could be used interchangeably throughout the project:

I mean research is knocking a billiard ball gently down a table to the other end and the role of the public bit is to just have to influence and push it to the left, push it to the right, give the researchers, oh it’s difficult to describe, isn’t it? Because it’s not, I understand entirely it’s not complete consultation and on some occasions it’s taken seriously. I think, put it this way, to keep the researchers in touch. CS03PPI02-01
To me, I mean, I think there are different levels at which you can involve people through the standard three levels. I mean, to me, we like to work with people as collaboratively as possible. I realise there is a role for consultative involvement in research but, for me, it’s being able to work in partnership really with members of the public to help design and to have ideas for research really. CS21Res02-01

Although none of our case studies was user-led, as described in the previous section some did have lay representatives as coapplicants or co-researchers (CS04, CS19, CS21 and CS23), although levels of involvement also varied. Although CS17 (see previous section) did involve lay representatives at all stages, researchers also raised as an issue the move towards lay representatives as coapplicants. There were concerns that this was becoming the ‘gold-standard’ of PPI and people questioned if all study designs are suited to having PPI representatives as coapplicants:

it is difficult to have coapplicants on the kind of research we do, because of the nature of it, you know, if a member of the public came up and said I think you should compare the level of HbA 1C [glycated haemoglobin] compared to glucose, they wouldn’t be a member of the public, they would be a scientist, to even know what the question was . . . because I think there is the idea that being coapplicants, and making videos is a measure of doing good PPI. CS17Res01-04

Nevertheless, some felt that funding was more likely with a PPI representative as coapplicant; but this was not confirmed by any of our funder respondents. However, there was clearly a lack of reflection on whether or not having lay coapplicants made any particular impact on the research process and outcomes.

  • Reflection, appraisal and evaluation

Only two of the case studies provided any evidence of systematically appraising the PPI contribution to their study. However, funders’ requirements (C1) for an evaluation of PPI in the final report were beginning to have an influence, but any evaluative work was less commonly a collaborative endeavour for a research team. In contrast, host organisations (C7) that had embedded PPI infrastructures were more likely to evaluate and fine-tune PPI processes in a collaborative way. Having developed over time, embedded PPI infrastructures also enabled positive relationships (C5) in which researchers and lay members could reflect honestly on what and what had not worked well. Table 17 illustrates the CMO configuration for this action.

TABLE 17

Context, mechanism and outcome configuration: reflection, appraisal and evaluation

Systematic appraisal of patient and public involvement

Of the two case studies with systematic appraisal, CS13 (see Box 16 ) had an annual evaluation, with a review of the PPI contribution and model at the panel annual general meeting. The researcher co-ordinating PPI ‘measures’ the extent of PPI against published best practice guides to assess if PPI can be of use in further phases of the research:

The NIHR, five or six points in the research cycle in which people should be involved, I’ve always bought into that notion, so we try and use that as a template for judging how we’re doing internally. CS13Res05-01

Case study 21 provided the RAPPORT study with numerous documents which recorded PPI activities and impact but currently did not formally evaluate PPI. However, the case study site was actively involved in piloting an evaluative framework for PPI with clear intentions to change its PPI practices in future to include systematic appraisal.

However, researchers often did not have the time or resources to record PPI activities and reflect on PPI input, and some did not see it as something they should be doing. Respondents from CS06 ( Box 24 ) saw PPI as an implicit part of the research process and hence not requiring discrete evaluation:

Case study 06: public health Hybrid model consisting of one-off events for less experienced PPI, and an advisory group including a more experienced PPI with more commitment/ongoing responsibility required. Member of the general public. Three development (more...)

I wouldn’t say it has added value, I think it’s actually fundamental to, to the research inquiry . . . it’s not just added value, it’s intrinsic to the inquiry. CS06PPI01-01

However, as the NPT radar plots illustrate (bold box), although there was no systematic evaluation of PPI, respondents did individually appraise PPI as worthwhile in the study.

Other researchers struggled to evaluate PPI because there was little guidance or knowledge on how to carry out this task and recognised: ‘it’s quite hard to evaluate I would have thought’ (CS08Res01-02). Despite the lack of systematic evaluation, some research projects did record PPI activities, providing a baseline to document PPI input.

For some researchers a lack of robust evidence on the value of PPI was a problem. In CS10 ( Box 25 ) it was explicitly recognised that what was seen as ‘worthwhile’ by the general public might not be seen in the same way by researchers:

Case study 10: public health Experts by experience, using a ‘consultation’ approach.

especially not to researchers. To people outside the world of research, I can reason very happily [on the value of PPI]. But researchers want evidence and that’s the holy grail, and I haven’t seen it yet. CS10Res04-01

The rather mixed view on the value of PPI within CS10 can be seen in the radar plot in the case study summary. Within the tracking radar plot, the impact of questioning the value of the PPI in this study is marked.

Enabling contexts for evaluating patient and public involvement

Funders’ requirements (C1) were a strong enabling context for evaluation. For example, the requirement to report on PPI when NIHR-funded projects were completed was a major incentive for researchers to review processes and benefits of PPI in the project. Indeed, some case studies agreed to be part of the RAPPORT study as an aid to meet this requirement. However, approaches to evaluating the outcomes and impact of PPI were shaped by the funding organisation’s stance towards PPI. The data from the programme management organisations strongly resonated with the methodological argument for PPI; hence, the organisations were actively seeking ways of evaluating the impact of PPI on research outcomes. Approaches cited, however systematic, seemed descriptive and biased towards ‘good news’: the collection of illustrative case studies and the specific identification of PPI in the final research report, as described below.

I ask that all the monitoring programme managers, if they spot something really interesting or good or unusual or positive, that they just let me know. And then I keep a spreadsheet of all of those for posterity, for, you know, when I start doing, we’re doing a lot of work on impact here . . . we’ll have more ability to really get in and look at good examples of PPI. Funder04

There was evidence that this focus on evaluation, although not fully assessing and comparing impact, was resulting in some modification to the funder’s PPI work, for example developing advice to support lay representatives on trial steering committees.

For the funding organisations framing PPI more in the engagement paradigm, evaluation was focused on the impact of public engagement activities, and a web-based tool was used for researchers to record their public engagement activities and outcomes. For the condition-specific medical charities, again perhaps shaped by their moral stance on PPI, there was anecdotal evidence of where PPI has had an observable impact: ‘I think that they [grant applicants] have an increased awareness of the fact that they have to write a good lay summary’ (Funder01). However, there was no systematic appraisal of this.

For lay representatives, a positive appraisal of PPI was shaped not only by a positive experience (C8), but also by personal outcomes. Described further later, these outcomes included increased understanding of their health condition:

I read some of the interviews from other patients . . . it really helped me because personally . . . reading about how people are suffering from it and I’m not the only one, other people are also going through the same sort of problems, yeah. So some people do get better, people still live a happy life. CS18PPI02-01

For others it was a sense of giving something back to the health-care system:

I then felt well if I can do anything, you know for the greater good, I was happy to do it and so I get out of it the feeling I’m making a contribution towards the research and the further development of treatment for patients with rheumatoid. CS14PPI01-01

A number of researchers also felt PPI was worthwhile to them personally beyond impact just on the research process and outcomes. Researchers spoke of PPI bringing them closer to patients or service users, and reminding the researcher about the real aim of the research:

remind you a bit why you’re doing it because sitting in front of a load of numbers you sort of think, you know you’re doing it for those people. Because that’s the population you’re working with. CS13Res01-01

A positive experience of PPI was often the start of the process to establish PPI as normal practice:

she’s really been the one that’s been my epiphany for understanding patient involvement more than anyone. CS08Res01-01

Equally, a negative experience of PPI could hold up this process for some time:

I did an informal questionnaire amongst patients who we saw in the secondary care clinic, research patients, asking them to identify, you know, suitable research topics. However, I didn’t find it was very useful, patients mainly said that research should be concentrating on identifying a cure for diabetes, and that’s not completely helpful as that’s like a very long-term goal in research . . . then that sort of coloured my views of PPI for a little while afterwards thinking, hmm, I’m not sure really what patients want to get out of it or whether they have enough knowledge about the research process and personnel involved to be able to contribute effectively. CS02Res02-01

Modifying future work

The majority of the case studies reflected on their PPI approaches only informally towards the end of the study, so there was minimal evidence of any changes within actual case studies. However, in a longitudinal cohort study (CS14) there was also evidence that being a case study within the RAPPORT study provided the opportunity for participants to reflect on PPI and plan things differently for the future:

you’re making me think [interviewer], maybe I should do a little leaflet to send out to show them all what we are doing with their information. So as I’ve been talking to you that’s something I will be doing differently and I’ll bring it up at the meeting that we should be sending them an update or feedback. CS14Res03-03

This case study ( Box 26 ) was supported by minimal PPI infrastructure but the impact of reflection can be seen in the tracking radar plots (bold box).

For the majority of case studies, either modifications to PPI approaches would be operationalised in future studies, or the influence of that particular case study was affecting PPI approaches within other studies:

What is great now, lots and lots of studies are coming through . . . other departments who weren’t doing any PPI or patients, it is forcing them, I have access to a group of volunteers, pre-screened; you need to do PPI to get them! . . . we are getting sport scientists, oncologist, all sorts of people; the meetings are becoming more and more interesting . . . now the meeting [panel] has such a wide diversity of studies that are being discussed. CS17Res01-03

Hence, while the CS17 (see Box 23 ) tracking radar plot showed minimal change in the reflexive monitoring segment, if expanded to the research environment in which it was hosted then a far more significant change could be noted.

Nevertheless, extensive future changes to PPI approaches could be inhibited by a lack of understanding of what is possible, as exemplified by CS09 ( Box 27 ):

Case study 09: IDD Two national representatives of two different support groups. Both PPI representatives sit on project advisory group; one of them carries out much of the qualitative analysis.

I don’t know how you go about involving patient and public in planning research, that maybe sounds a bit silly; in my mind I have a big question mark about how it works: before you recruit anyone to the study you need ethical approval, and to me asking patients potentially what they want research to entail, is in a way recruiting them to a mini study before the main study. CS09Res02-01

While the radar plots indicate a comparatively embedded level of PPI, future potential impact of PPI is constrained by researchers’ beliefs. This reinforces findings presented earlier where potential PPI impact was inhibited by boundaries set by the research team.

  • Impact and outcomes of patient and public involvement

As presented in each CMO configuration, case study actions led to a number of methodological and moral impacts and outcomes. This section draws on the interview and documentary data to provide evidence of the methodological impacts and outcomes of PPI within the case studies. Here we define impact as the immediate effects of PPI, which may be intended as part of the objective for PPI within each study, or unintended. Outcomes are longer-term effects of PPI in relation to the overall goal for PPI in each study. 160 Eight of the 22 case studies concluded during the RAPPORT data collection period, so participants could provide summative assessments of the impact and also possible longer-term outcomes of PPI. However, it should be recognised that there are likely to be longer-term outcomes of studies that were not possible to capture within the time scale of the RAPPORT study.

Impact and/or outcomes were described within 13 stages of the research cycle/process and there were a range of topic areas with evidence of impact and outcomes ( Table 18 ). The following section provides evidence of PPI methodological impact and outcomes with specific examples from the 22 case studies. Impact and outcomes are applicable only to certain research designs and, of course, are a function of the original PPI objectives and overall goal.

TABLE 18

Methodological impact of PPI by topic area

Research priority and question setting

Five of the case studies reported that PPI representatives had been involved in research priority setting. For example, the panel in CS17 had input into deciding which research should be funded, although we received no documentary evidence to show the impact on decision-making. We were provided evidence of PPI impact in identifying research questions. For example, the research centre hosting CS21 has a large PPI group who are encouraged to put forward research questions, and this particular case study originated from one of the parents. The structure of the research centre and the priority that this organisation gives to PPI ensure that the ideas relevant to service users are carried out:

Because the very idea of the whole thing came from a parent, it’s been a very natural process to have families involved in it all of the time, and I think that’s the beauty of getting the idea from the family. You don’t have to then try and shoehorn PPI in, it’s already there. So, it’s just been from the word go. CS21Res01-01

Linking to the wider community

Four case studies utilised PPI to provide links to the wider community. Case study 02 exemplified this approach, with the single lay representative on the steering committee consulting with wider range of people from the study target population. A newsletter to this group provides evidence of the impact of this approach ( Box 28 ).

Documentary evidence: case study 02 [Patient organisation] members recommended changes to the draft proposal and these were incorporated into the final version and into the current protocol. The suggestions included:

In CS23, this PPI bridging role to the wider population (in this case younger people) was done via social media and was an effective way of getting one-off input from an often less-heard group. This input was used as a basis for a practice-focused article and also informed the development of the study ( Box 29 ).

Documentary evidence: case study 23 . . . what apps and websites are YPD [young people with diabetes] using? In order to review the use of apps and other online resources by YPDs, one of the authors (PPI rep.) discussed the use of apps (more...)

Lay representatives were also used as a link to recruit study participants. Examples included writing articles for newsletters to encourage participants to take part, being filmed as part of the recruitment video, using social media or approaching people directly through their networks (support groups).

Such connections with other groups of members of the public or service users proved to be valuable in recruitment, and in harnessing a wider range of (less accessible) PPI representatives/experiences, reassuring researchers who were concerned about the PPI representatives not being a ‘typical’ lay person.

Marketing the study

Two of the studies had PPI input regarding study logos, and in the first study the logo was changed ( Box 30 ).

Documentary evidence: case study 06 There was a lot of discussion about the photographs used. They preferred the picture of the couple walking in the wood, as this looked active and upbeat. However, they felt that there was also value in the older woman (more...)

However, in CS19 PPI advice was not taken on board, as the logo had been already commissioned and developed by the team (and PPI coapplicant), but it was later criticised as being potentially insensitive by steering group PPI representatives:

it was about their logo [. . .] I just hated it on sight, and their response to that was, ‘But we paid someone to do it and . . . maybe . . . [other] people wouldn’t feel like that.’ CS19PPI02

Design of study

Patient and public involvement representatives made comments on the protocol and design of the study in 13 of the case studies, particularly regarding lay summaries, data collection instruments and study information ( Box 31 ). In other case studies PPI representatives were consulted over study design; for example, they were asked whether a RCT or partial randomised control design should be used, and PPI representatives’ suggestion of a RCT design (CS07) was accepted. In another case study the PPI representatives were asked if they approved of particular methods of accessing patients’ notes (CS01). Data collection tools such as questionnaires were ‘softened’ by PPI representatives in terms of language and sensitivity (CS09, CS21).

Documentary evidence: case study 13 It was suggested at the last meeting that the third health-check webpage is too heavy on text and if the big paragraphs could be reduced with the option to expand if someone is interested in reading more information. (more...)

Safety of study

Involving patients’ groups in the governance of a study had evidence of potentially improving patient safety. In the original proposal of CS02, the researcher conceded that the research study was presented in a very clinical fashion and, because it was asking people to reduce the amount of a particular drug that they were taking, the safety element (from the patient’s point of view) had not been considered. PPI views (through a national charity panel) changed the application to include a safety questionnaire:

when I put together the original application, it didn’t really have much in terms of the safety element because I had taken it for granted that people are already on [x drug], reducing the dose wouldn’t make a big difference and I would have seen it in a clinical fashion, but as soon as we got the patients on board and had their comments coming through, one of the things that seemed to be coming through was a concern, or a potential concern from the patients that would it make them feel unwell or would it do anything to them? So therefore we then added an extra element asking patients about how they felt, safety questionnaires. CS02Res01-01

The outcome of PPI here was reassurance for patients in terms of safety and also improved recruitment rates, and a 3-month visit (for reassurance) was added to the study design for participants.

Design of intervention

In those studies which contained an intervention as part of their study design, PPI representatives helped to design or make suggestions to existing interventions to make them more acceptable/feasible. In CS03 one PPI representative suggested there should be more content on pre-pregnancy and diabetes mellitus, and the documentation confirmed that more was added into the resource intervention ( Box 32 ).

Documentary evidence: case study 03 I fully understand that you don’t want to go into the complexities of pregnancy with diabetes but I feel more is needed to inform women of the importance of pre-pregnancy planning and quick action once they (more...)

When the intervention was a questionnaire (CS04, CS07) the questionnaire was altered to include items not previously considered by the researcher:

I’m sort of embarrassed to admit it, but I went to that meeting thinking, ‘I know everything that should go in this questionnaire’, but I so didn’t, and loads of stuff came out in that meeting that I just never would have thought of. CS04Res01-01

In another case study (CS07) PPI representatives were involved in the validation of 260 pre- and post-questionnaires (which were used as part of the intervention). The PPI representatives took the questionnaire back to their local user groups and asked them to complete the questionnaire as a pilot. However, there was also evidence that researchers perceived an unintended outcome of PPI. In CS23 the CI (who was also a clinician) felt that the PPI representatives had steered the project off course, and that the interventions developed were neither innovative nor adequately focused on the research question.

Research ethics submission

Two of the case studies felt that having PPI helped their ethics submission by saying that materials had been viewed and approved by PPI representatives:

they [research ethics committee] take note it, of course the committees have their own lay people and I mean the one thing about lay people is they’re individuals like all of us, it’s a bit like a peer review and you might get lay members of the panel who don’t really agree but they take note of it and I think it carries quite a bit of weight, doesn’t always carry the day though. CS01Res02-01

Recruitment

One of the most frequently stated outcomes for PPI in our case studies was a perceived increase in recruitment rates to the research study (18 of the 22 case studies). Researchers commonly attributed recruitment success to the PPI input to materials (suggestions on layout, size, language, colour, length, readability, clarity and design; evidenced by tracked changes/before and after versions of documents) used for recruitment (PIS, invitation letters, consent forms). Suggested changes were made either directly by the PPI representatives themselves or by taking materials back to wider reference groups for further comments; for example parents showing the PIS to their children. PPI representatives made changes to language such as taking out the word ‘mortality’ or explaining technical words such as ‘lung function’. They introduced a summary section at the start of the PIS and produced information in a small, credit card-sized, format for people to carry in their wallets. Changes also included images of actual people wearing equipment or lying on scanners, and extra information about the length of procedure and the weight and size of any equipment was added (CS13 PIS).

One researcher felt able to quantify the increase in recruitment because of such PPI changes. A number of different versions of the PIS and invitation letter had been submitted to ethics committees:

we changed a few things but we did [a] stage [at a] time so we could see what had an impact, and that certainly did increase recruitment by, only you know, 1 or 2%, but 1 or 2% when you’re sending out thousands a month . . . CS12Res02-01

Outcome measures

Research teams advocated the use of PPI for outcome measures that were relevant to patients; this was particularly relevant to one arthritis study:

it was appreciated that there were certain things that we were measuring that we thought were really important, these patients actually weren’t interested in at all and didn’t deem relevant, whereas other issues we didn’t think were . . . well, we thought they were important, obviously, otherwise we wouldn’t measure them, but we didn’t realise how important they were to patients. CS14Res01-01

There was qualifying evidence here that the outcome measures had been changed or added to in the research design. Respondents also reported that this change of emphasis was fed into clinical guidelines, which may have an impact on patient experience.

Data analysis and collection

Two studies had PPI representatives involved directly in data collection. The PPI representative in CS18 was involved in data analysis; she was asked because of her cultural knowledge and to reassure the researchers that the analysis resonated with her experience of the ethnic ‘community’:

I want to check with the community that I’m not sort of completely going way off track here so I guess in some ways that was her main role, more than in this situation the experience of living with the illness really, it was actually her cultural knowledge that was most helpful. CS18Res01-01

In one case study where this PPI role could have been applicable but was not utilised (CS21), this was a deliberate restriction because of ethical considerations; many of the study participants would have been known to the PPI representatives.

Patient and public involvement representatives also made a contribution to data analysis ( Box 33 ).

Documentary evidence: case study 09 As you say, the difference in preference is interesting. What I could really do with – if you ever have five minutes – is for you just to talk me through one or two of the tables as I am rubbish at interpreting (more...)

The impact of this was clearly described by the researcher:

When I initially did a straight comparison women’s views versus health professional’s views, [PPI02] suggested I break down the women, into those that had experience with [xxx] or [xxxx], compared them to women who haven’t had any problem [xxxx] and we found quite big differences between the two groups. CS09Res01-02

Dissemination

Two of the case studies (CS17 and CS21) mentioned that the PPI representatives had presented the study findings at conferences, and six examples of academic papers with PPI representatives as coauthors were submitted to the RAPPORT study. One of the PPI representatives, who was working as an academic researcher 3 days a week on the project, was first author of a paper (and her organisation was the charity mentioned in the paper). Other representatives were mentioned in the acknowledgements at the end of the paper. Some case studies in the RAPPORT study had not yet reached dissemination phases; however, our tracking interviews suggested that, in a number of cases where it had been planned that PPI representatives would be involved in dissemination, this had not happened.

Moral impact and outcomes

In addition to the outcomes which were identified in terms of the research project, the researchers and PPI representatives also identified personal outcomes associated with their PPI role. The personal benefits of PPI have been well documented, and those reported here echo previous studies. These included increased self-confidence and mental challenge. The PPI role helped people to keep mentally active in retirement or unemployment and provided the possibility of leading to other roles or responsibilities:

. . . enriches our research but also enriches their lives. CS21Res01
. . . it just opens up a world of opportunities. CS21PPI01

Interestingly, some PPI representatives spoke of the benefits of their involvement to the wider society: ‘maybe it’ll change the world a little bit’ (CS11PPI02-01). In CS03, the PPI representatives felt that they could pass back information to their wider network and again be ‘boundary spanners’ (which Williams 161 describes as ‘individuals who have a dedicated job role or responsibility to work in collaborative environments’) between the academic world and the patient community:

I have met since my diagnosis other people who’ve had [condition] for many many years who haven’t necessarily had access to much information or they haven’t, or they have had access to information and services but it’s been a bit sporadic and I always wanted to kind of pass that information along or back to people that I’d met, so . . . I’ve kind of been a lay tutor. CS03PPI04-01

Longer-term outcomes

The RAPPORT study was designed to include studies that concluded during our data collection period, with the expectation that outcomes of PPI could be summatively assessed. Among the eight that were completed, we found no evidence of any immediate outcomes of PPI for the research findings. However, out of these eight studies, five had demonstrated clear embedding of PPI and interestingly it was these studies that clearly identified the outcome as developing further grant applications, as more research was required. These five case studies were continuing to work with their lay representatives to generate further research questions. Out of the remaining three, one was in follow-up, we could find no evidence from the other two case studies of any particular outcome, and from a dissemination perspective there was nothing publicly accessible providing results or outcomes of the studies. It is clear that, as in all evaluation of research impact, longer-term outcomes influenced by PPI need an extensive time to detect.

Collective understanding about the purpose and role of PPI was an important mechanism leading to positive outcomes, and was enabled by training and certain topics and study designs. Values quite clearly shaped this understanding, and there was some questioning of whether or not PPI was appropriate in all study designs. Three main models of PPI were identified: a bounded, one-off model, an outreach model and a fully intertwined model. Even in research settings with minimal PPI infrastructure, there was clear evidence that establishing and maintaining relationships was crucial and required time. PPI as a dynamic process was significantly compromised when relationships broke down. It was also clear that a dual role (participant/involvee) was relatively common, and that an unintended consequence of the evolving national and regional PPI structure was an outsourcing of PPI, with associated researcher disengagement. These key areas will now be explored further in the discussion.

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  • Cite this Page Wilson P, Mathie E, Keenan J, et al. ReseArch with Patient and Public invOlvement: a RealisT evaluation – the RAPPORT study. Southampton (UK): NIHR Journals Library; 2015 Sep. (Health Services and Delivery Research, No. 3.38.) Chapter 6, Findings from the case studies.
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  • Published: 14 February 2024

Critical transitions in the Amazon forest system

  • Bernardo M. Flores   ORCID: orcid.org/0000-0003-4555-5598 1 ,
  • Encarni Montoya   ORCID: orcid.org/0000-0002-4690-190X 2 ,
  • Boris Sakschewski   ORCID: orcid.org/0000-0002-7230-9723 3 ,
  • Nathália Nascimento   ORCID: orcid.org/0000-0003-4819-0811 4 ,
  • Arie Staal   ORCID: orcid.org/0000-0001-5409-1436 5 ,
  • Richard A. Betts   ORCID: orcid.org/0000-0002-4929-0307 6 , 7 ,
  • Carolina Levis   ORCID: orcid.org/0000-0002-8425-9479 1 ,
  • David M. Lapola 8 ,
  • Adriane Esquível-Muelbert   ORCID: orcid.org/0000-0001-5335-1259 9 , 10 ,
  • Catarina Jakovac   ORCID: orcid.org/0000-0002-8130-852X 11 ,
  • Carlos A. Nobre 4 ,
  • Rafael S. Oliveira   ORCID: orcid.org/0000-0002-6392-2526 12 ,
  • Laura S. Borma 13 ,
  • Da Nian   ORCID: orcid.org/0000-0002-2320-5223 3 ,
  • Niklas Boers   ORCID: orcid.org/0000-0002-1239-9034 3 , 14 ,
  • Susanna B. Hecht 15 ,
  • Hans ter Steege   ORCID: orcid.org/0000-0002-8738-2659 16 , 17 ,
  • Julia Arieira 18 ,
  • Isabella L. Lucas 19 ,
  • Erika Berenguer   ORCID: orcid.org/0000-0001-8157-8792 20 ,
  • José A. Marengo 21 , 22 , 23 ,
  • Luciana V. Gatti 13 ,
  • Caio R. C. Mattos   ORCID: orcid.org/0000-0002-8635-3901 24 &
  • Marina Hirota   ORCID: orcid.org/0000-0002-1958-3651 1 , 12 , 25  

Nature volume  626 ,  pages 555–564 ( 2024 ) Cite this article

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  • Climate and Earth system modelling
  • Ecosystem ecology
  • Ecosystem services
  • Sustainability

The possibility that the Amazon forest system could soon reach a tipping point, inducing large-scale collapse, has raised global concern 1 , 2 , 3 . For 65 million years, Amazonian forests remained relatively resilient to climatic variability. Now, the region is increasingly exposed to unprecedented stress from warming temperatures, extreme droughts, deforestation and fires, even in central and remote parts of the system 1 . Long existing feedbacks between the forest and environmental conditions are being replaced by novel feedbacks that modify ecosystem resilience, increasing the risk of critical transition. Here we analyse existing evidence for five major drivers of water stress on Amazonian forests, as well as potential critical thresholds of those drivers that, if crossed, could trigger local, regional or even biome-wide forest collapse. By combining spatial information on various disturbances, we estimate that by 2050, 10% to 47% of Amazonian forests will be exposed to compounding disturbances that may trigger unexpected ecosystem transitions and potentially exacerbate regional climate change. Using examples of disturbed forests across the Amazon, we identify the three most plausible ecosystem trajectories, involving different feedbacks and environmental conditions. We discuss how the inherent complexity of the Amazon adds uncertainty about future dynamics, but also reveals opportunities for action. Keeping the Amazon forest resilient in the Anthropocene will depend on a combination of local efforts to end deforestation and degradation and to expand restoration, with global efforts to stop greenhouse gas emissions.

The Amazon forest is a complex system of interconnected species, ecosystems and human cultures that contributes to the well-being of people globally 1 . The Amazon forest holds more than 10% of Earth’s terrestrial biodiversity, stores an amount of carbon equivalent to 15–20 years of global CO 2 emissions (150–200 Pg C), and has a net cooling effect (from evapotranspiration) that helps to stabilize the Earth’s climate 1 , 2 , 3 . The forest contributes up to 50% of rainfall in the region and is crucial for moisture supply across South America 4 , allowing other biomes and economic activities to thrive in regions that would otherwise be more arid, such as the Pantanal wetlands and the La Plata river basin 1 . Large parts of the Amazon forest, however, are projected to experience mass mortality events due to climatic and land use-related disturbances in the coming decades 5 , 6 , potentially accelerating climate change through carbon emissions and feedbacks with the climate system 2 , 3 . These impacts would also involve irreversible loss of biodiversity, socioeconomic and cultural values 1 , 7 , 8 , 9 . The Amazon is home to more than 40 million people, including 2.2 million Indigenous peoples of more than 300 ethnicities, as well as afrodescendent and local traditional communities 1 . Indigenous peoples and local communities (IPLCs) would be harmed by forest loss in terms of their livelihoods, lifeways and knowledge systems that inspire societies globally 1 , 7 , 9 .

Understanding the risk of such catastrophic behaviour requires addressing complex factors that shape ecosystem resilience 10 . A major question is whether a large-scale collapse of the Amazon forest system could actually happen within the twenty-first century, and if this would be associated with a particular tipping point. Here we synthesize evidence from paleorecords, observational data and modelling studies of critical drivers of stress on the system. We assess potential thresholds of those drivers and the main feedbacks that could push the Amazon forest towards a tipping point. From examples of disturbed forests across the Amazon, we analyse the most plausible ecosystem trajectories that may lead to alternative stable states 10 . Moreover, inspired by the framework of ‘planetary boundaries’ 11 , we identify climatic and land use boundaries that reveal a safe operating space for the Amazon forest system in the Anthropocene epoch 12 .

Theory and concepts

Over time, environmental conditions fluctuate and may cause stress on ecosystems (for example, lack of water for plants). When stressing conditions intensify, some ecosystems may change their equilibrium state gradually, whereas others may shift abruptly between alternative stable states 10 . A ‘tipping point’ is the critical threshold value of an environmental stressing condition at which a small disturbance may cause an abrupt shift in the ecosystem state 2 , 3 , 13 , 14 , accelerated by positive feedbacks 15 (see Extended Data Table 1 ). This type of behaviour in which the system gets into a phase of self-reinforcing (runaway) change is often referred to as ‘critical transition’ 16 . As ecosystems approach a tipping point, they often lose resilience while still remaining close to equilibrium 17 . Thus, monitoring changes in ecosystem resilience and in key environmental conditions may enable societies to manage and avoid critical transitions. We adopt the concept of ‘ecological resilience’ 18 (hereafter ‘resilience’), which refers to the ability of an ecosystem to persist with similar structure, functioning and interactions, despite disturbances that push it to an alternative stable state. The possibility that alternative stable states (or bistability) may exist in a system has important implications, because the crossing of tipping points may be irreversible for the time scales that matter to societies 10 . Tropical terrestrial ecosystems are a well-known case in which critical transitions between alternative stable states may occur (Extended Data Fig. 1 ).

Past dynamics

The Amazon system has been mostly covered by forest throughout the Cenozoic era 19 (for 65 million years). Seven million years ago, the Amazon river began to drain the massive wetlands that covered most of the western Amazon, allowing forests to expand over grasslands in that region. More recently, during the drier and cooler conditions of the Last Glacial Maximum 20 (LGM) (around 21,000 years ago) and of the mid-Holocene epoch 21 (around 6,000 years ago), forests persisted even when humans were already present in the landscape 22 . Nonetheless, savannas expanded in peripheral parts of the southern Amazon basin during the LGM and mid-Holocene 23 , as well as in the northeastern Amazon during the early Holocene (around 11,000 years ago), probably influenced by drier climatic conditions and fires ignited by humans 24 , 25 . Throughout the core of the Amazon forest biome, patches of white-sand savanna also expanded in the past 20,000–7,000 years, driven by sediment deposition along ancient rivers 26 , and more recently (around 800 years ago) owing to Indigenous fires 27 . However, during the past 3,000 years, forests have been mostly expanding over savanna in the southern Amazon driven by increasingly wet conditions 28 .

Although palaeorecords suggest that a large-scale Amazon forest collapse did not occur within the past 65 million years 19 , they indicate that savannas expanded locally, particularly in the more seasonal peripheral regions when fires ignited by humans were frequent 23 , 24 . Patches of white-sand savanna also expanded within the Amazon forest owing to geomorphological dynamics and fires 26 , 27 . Past drought periods were usually associated with much lower atmospheric CO 2 concentrations, which may have reduced water-use efficiency of trees 29 (that is, trees assimilated less carbon during transpiration). However, these periods also coincided with cooler temperatures 20 , 21 , which probably reduced water demand by trees 30 . Past drier climatic conditions were therefore very different from the current climatic conditions, in which observed warming trends may exacerbate drought impacts on the forest by exposing trees to unprecedented levels of water stress 31 , 32 .

Global change impacts on forest resilience

Satellite observations from across the Amazon suggest that forest resilience has been decreasing since the early 2000s 33 , possibly as a result of global changes. In this section, we synthesize three global change impacts that vary spatially and temporally across the Amazon system, affecting forest resilience and the risk of critical transitions.

Regional climatic conditions

Within the twenty-first century, global warming may cause long-term changes in Amazonian climatic conditions 2 . Human greenhouse gas emissions continue to intensify global warming, but the warming rate also depends on feedbacks in the climate system that remain uncertain 2 , 3 . Recent climate models of the 6th phase of the Coupled Model Intercomparison Project (CMIP6) agree that in the coming decades, rainfall conditions will become more seasonal in the eastern and southern Amazonian regions, and temperatures will become higher across the entire Amazon 1 , 2 . By 2050, models project that a significant increase in the number of consecutive dry days by 10−30 days and in annual maximum temperatures by 2–4 °C, depending on the greenhouse gas emission scenario 2 . These climatic conditions could expose the forest to unprecedented levels of vapour pressure deficit 31 and consequently water stress 30 .

Satellite observations of climatic variability 31 confirm model projections 2 , showing that since the early 1980s, the Amazonian region has been warming significantly at an average rate of 0.27 °C per decade during the dry season, with the highest rates of up to 0.6 °C per decade in the centre and southeast of the biome (Fig. 1a ). Only a few small areas in the west of the biome are significantly cooling by around 0.1 °C per decade (Fig. 1a ). Dry season mean temperature is now more than 2 °C higher than it was 40 years ago in large parts of the central and southeastern Amazon. If trends continue, these areas could potentially warm by over 4 °C by 2050. Maximum temperatures during the dry season follow a similar trend, rising across most of the biome (Extended Data Fig. 2 ), exposing the forest 34 and local peoples 35 to potentially unbearable heat. Rising temperatures will increase thermal stress, potentially reducing forest productivity and carbon storage capacity 36 and causing widespread leaf damage 34 .

figure 1

a , Changes in the dry season (July–October) mean temperature reveal widespread warming, estimated using simple regressions between time and temperature observed between 1981 and 2020 (with P  < 0.1). b , Potential ecosystem stability classes estimated for year 2050, adapted from current stability classes (Extended Data Fig. 1b ) by considering only areas with significant regression slopes between time and annual rainfall observed from 1981 through 2020 (with P  < 0.1) (see Extended Data Fig. 3 for areas with significant changes). c , Repeated extreme drought events between 2001–2018 (adapted from ref. 39 ). d , Road network from where illegal deforestation and degradation may spread. e , Protected areas and Indigenous territories reduce deforestation and fire disturbances. f , Ecosystem transition potential (the possibility of forest shifting into an alternative structural or compositional state) across the Amazon biome by year 2050 inferred from compounding disturbances ( a – d ) and high-governance areas ( e ). We excluded accumulated deforestation until 2020 and savannas. Transition potential rises with compounding disturbances and varies as follows: less than 0 (in blue) as low; between 1 and 2 as moderate (in yellow); more than 2 as high (orange–red). Transition potential represents the sum of: (1) slopes of dry season mean temperature (as in a , multiplied by 10); (2) ecosystem stability classes estimated for year 2050 (as in b ), with 0 for stable forest, 1 for bistable and 2 for stable savanna; (3) accumulated impacts from extreme drought events, with 0.2 for each event; (4) road proximity as proxy for degrading activities, with 1 for pixels within 10 km from a road; (5) areas with higher governance within protected areas and Indigenous territories, with −1 for pixels inside these areas. For more details, see  Methods .

Since the early 1980s, rainfall conditions have also changed 31 . Peripheral and central parts of the Amazon forest are drying significantly, such as in the southern Bolivian Amazon, where annual rainfall reduced by up to 20 mm yr −1 (Extended Data Fig. 3a ). By contrast, parts of the western and eastern Amazon forest are becoming wetter, with annual rainfall increasing by up to 20 mm yr −1 . If these trends continue, ecosystem stability (as in Extended Data Fig. 1 ) will probably change in parts of the Amazon by 2050, reshaping forest resilience to disturbances (Fig. 1b and Extended Data Fig. 3b ). For example, 6% of the biome may change from stable forest to a bistable regime in parts of the southern and central Amazon. Another 3% of the biome may pass the critical threshold in annual rainfall into stable savanna in the southern Bolivian Amazon. Bistable areas covering 8% of the biome may turn into stable forest in the western Amazon (Peru and Bolivia), thus becoming more resilient to disturbances. For comparison with satellite observations, we used projections of ecosystem stability by 2050 based on CMIP6 model ensembles for a low (SSP2–4.5) and a high (SSP5–8.5) greenhouse gas emission scenario (Extended Data Fig. 4 and Supplementary Table 1 ). An ensemble with the 5 coupled models that include a dynamic vegetation module indicates that 18–27% of the biome may transition from stable forest to bistable and that 2–6% may transition to stable savanna (depending on the scenario), mostly in the northeastern Amazon. However, an ensemble with all 33 models suggests that 35–41% of the biome could become bistable, including large areas of the southern Amazon. The difference between both ensembles is possibly related to the forest–rainfall feedback included in the five coupled models, which increases total annual rainfall and therefore the stable forest area along the southern Amazon, but only when deforestation is not included in the simulations 4 , 37 . Nonetheless, both model ensembles agree that bistable regions will expand deeper into the Amazon, increasing the risk of critical transitions due to disturbances (as implied by the existence of alternative stable states; Extended Data Fig. 1 ).

Disturbance regimes

Within the remaining Amazon forest area, 17% has been degraded by human disturbances 38 , such as logging, edge effects and understory fires, but if we consider also the impacts from repeated extreme drought events in the past decades, 38% of the Amazon could be degraded 39 . Increasing rainfall variability is causing extreme drought events to become more widespread and frequent across the Amazon (Fig. 1c ), together with extreme wet events and convective storms that result in more windthrow disturbances 40 . Drought regimes are intensifying across the region 41 , possibly due to deforestation 42 that continues to expand within the system (Extended Data Fig. 5 ). As a result, new fire regimes are burning larger forest areas 43 , emitting more carbon to the atmosphere 44 and forcing IPLCs to readapt 45 . Road networks (Fig. 1d ) facilitate illegal activities, promoting more deforestation, logging and fire spread throughout the core of the Amazon forest 38 , 39 . The impacts of these pervasive disturbances on biodiversity and on IPLCs will probably affect ecosystem adaptability (Box 1 ), and consequently forest resilience to global changes.

Currently, 86% of the Amazon biome may be in a stable forest state (Extended Data Fig. 1b ), but some of these stable forests are showing signs of fragility 33 . For instance, field evidence from long-term monitoring sites across the Amazon shows that tree mortality rates are increasing in most sites, reducing carbon storage 46 , while favouring the replacement by drought-affiliated species 47 . Aircraft measurements of vertical carbon flux between the forest and atmosphere reveal how southeastern forests are already emitting more carbon than they absorb, probably because of deforestation and fire 48 .

As bistable forests expand deeper into the system (Fig. 1b and Extended Data Fig. 4 ), the distribution of compounding disturbances may indicate where ecosystem transitions are more likely to occur in the coming decades (Fig. 1f ). For this, we combined spatial information on warming and drying trends, repeated extreme drought events, together with road networks, as proxy for future deforestation and degradation 38 , 39 . We also included protected areas and Indigenous territories as areas with high forest governance, where deforestation and fire regimes are among the lowest within the Amazon 49 (Fig. 1e ). This simple additive approach does not consider synergies between compounding disturbances that could trigger unexpected ecosystem transitions. However, by exploring only these factors affecting forest resilience and simplifying the enormous Amazonian complexity, we aimed to produce a simple and comprehensive map that can be useful for guiding future governance. We found that 10% of the Amazon forest biome has a relatively high transition potential (more than 2 disturbance types; Fig. 1f ), including bistable forests that could transition into a low tree cover state near savannas of Guyana, Venezuela, Colombia and Peru, as well as stable forests that could transition into alternative compositional states within the central Amazon, such as along the BR319 and Trans-Amazonian highways. Smaller areas with high transition potential were found scattered within deforestation frontiers, where most forests have been carved by roads 50 , 51 . Moreover, 47% of the biome has a moderate transition potential (more than 1 disturbance type; Fig. 1f ), including relatively remote parts of the central Amazon where warming trends and repeated extreme drought events overlap (Fig. 1a,c ). By contrast, large remote areas covering 53% of the biome have low transition potential, mostly reflecting the distribution of protected areas and Indigenous territories (Fig. 1e ). If these estimates, however, considered projections from CMIP6 models and their relatively broader areas of bistability (Extended Data Fig. 4 ), the proportion of the Amazon forest that could transition into a low tree cover state would be much larger.

Box 1 Ecosystem adaptability

We define ‘ecosystem adaptability’ as the capacity of an ecosystem to reorganize and persist in the face of environmental changes. In the past, many internal mechanisms have probably contributed to ecosystem adaptability, allowing Amazonian forests to persist during times of climate change. In this section we synthesize two of these internal mechanisms, which are now being undermined by global change.

Biodiversity

Amazonian forests are home to more than 15,000 tree species, of which 1% are dominant and the other 99% are mostly rare 107 . A single forest hectare in the central and northwestern Amazon can contain more than 300 tree species (Extended Data Fig. 7a ). Such tremendous tree species diversity can increase forest resilience by different mechanisms. Tree species complementarity increases carbon storage, accelerating forest recovery after disturbances 108 . Tree functional diversity increases forest adaptability to climate chance by offering various possibilities of functioning 99 . Rare species provide ‘ecological redundancy’, increasing opportunities for replacement of lost functions when dominant species disappear 109 . Diverse forests are also more likely to resist severe disturbances owing to ‘response diversity’ 110 —that is, some species may die, while others persist. For instance, in the rainy western Amazon, drought-resistant species are rare but present within tree communities 111 , implying that they could replace the dominant drought-sensitive species in a drier future. Diversity of other organisms, such as frugivores and pollinators, also increases forest resilience by stabilizing ecological networks 15 , 112 . Considering that half of Amazonian tree species are estimated to become threatened (IUCN Red list) by 2050 owing to climate change, deforestation and degradation 8 , biodiversity losses could contribute to further reducing forest resilience.

Indigenous peoples and local communities

Globally, Indigenous peoples and local communities (IPLCs) have a key role in maintaining ecosystems resilient to global change 113 . Humans have been present in the Amazon for at least 12,000 years 114 and extensively managing landscapes for 6,000 years 22 . Through diverse ecosystem management practices, humans built thousands of earthworks and ‘Amazon Dark Earth’ sites, and domesticated plants and landscapes across the Amazon forest 115 , 116 . By creating new cultural niches, humans partly modified the Amazonian flora 117 , 118 , increasing their food security even during times of past climate change 119 , 120 without the need for large-scale deforestation 117 . Today, IPLCs have diverse ecological knowledge about Amazonian plants, animals and landscapes, which allows them to quickly identify and respond to environmental changes with mitigation and adaptation practices 68 , 69 . IPLCs defend their territories against illegal deforestation and land use disturbances 49 , 113 , and they also promote forest restoration by expanding diverse agroforestry systems 121 , 122 . Amazonian regions with the highest linguistic diversity (a proxy for ecological knowledge diversity 123 ) are found in peripheral parts of the system, particularly in the north-west (Extended Data Fig. 7b ). However, consistent loss of Amazonian languages is causing an irreversible disruption of ecological knowledge systems, mostly driven by road construction 7 . Continued loss of ecological knowledge will undermine the capacity of IPLCs to manage and protect Amazonian forests, further reducing their resilience to global changes 9 .

CO 2 fertilization

Rising atmospheric CO 2 concentrations are expected to increase the photosynthetic rates of trees, accelerating forest growth and biomass accumulation on a global scale 52 . In addition, CO 2 may reduce water stress by increasing tree water-use efficiency 29 . As result, a ‘CO 2 fertilization effect’ could increase forest resilience to climatic variability 53 , 54 . However, observations from across the Amazon 46 suggest that CO 2 -driven accelerations of tree growth may have contributed to increasing tree mortality rates (trees grow faster but also die earlier), which could eventually neutralize the forest carbon sink in the coming decades 55 . Moreover, increases in tree water-use efficiency may reduce forest transpiration and consequently atmospheric moisture flow across the Amazon 53 , 56 , potentially reducing forest resilience in the southwest of the biome 4 , 37 . Experimental evidence suggests that CO 2 fertilization also depends on soil nutrient availability, particularly nitrogen and phosphorus 57 , 58 . Thus, it is possible that in the fertile soils of the western Amazon and Várzea floodplains, forests may gain resilience from increasing atmospheric CO 2 (depending on how it affects tree mortality rates), whereas on the weathered (nutrient-poor) soils across most of the Amazon basin 59 , forests might not respond to atmospheric CO 2 increase, particularly on eroded soils within deforestation frontiers 60 . In sum, owing to multiple interacting factors, potential responses of Amazonian forests to CO 2 fertilization are still poorly understood. Forest responses depend on scale, with resilience possibly increasing at the local scale on relatively more fertile soils, but decreasing at the regional scale due to reduced atmospheric moisture flow.

Local versus systemic transition

Environmental heterogeneity.

Environmental heterogeneity can reduce the risk of systemic transition (large-scale forest collapse) because when stressing conditions intensify (for example, rainfall declines), heterogeneous forests may transition gradually (first the less resilient forest patches, followed by the more resilient ones), compared to homogeneous forests that may transition more abruptly 17 (all forests transition in synchrony). Amazonian forests are heterogeneous in their resilience to disturbances, which may have contributed to buffering large-scale transitions in the past 37 , 61 , 62 . At the regional scale, a fundamental heterogeneity factor is rainfall and how it translates into water stress. Northwestern forests rarely experience water stress, which makes them relatively more resilient than southeastern forests that may experience water stress in the dry season, and therefore are more likely to shift into a low tree cover state. As a result of low exposure to water deficit, most northwestern forests have trees with low drought resistance and could suffer massive mortality if suddenly exposed to severe water stress 32 . However, this scenario seems unlikely to occur in the near future (Fig. 1 ). By contrast, most seasonal forest trees have various strategies to cope with water deficit owing to evolutionary and adaptive responses to historical drought events 32 , 63 . These strategies may allow seasonal forests to resist current levels of rainfall fluctuations 32 , but seasonal forests are also closer to the critical rainfall thresholds (Extended Data Fig. 1 ) and may experience unprecedented water stress in the coming decades (Fig. 1 ).

Other key heterogeneity factors (Extended Data Fig. 6 ) include topography, which determines plant access to groundwater 64 , and seasonal flooding, which increases forest vulnerability to wildfires 65 . Future changes in rainfall regimes will probably affect hydrological regimes 66 , exposing plateau (hilltop) forests to unprecedented water stress, and floodplain forests to extended floods, droughts and wildfires. Soil fertility is another heterogeneity factor that may affect forest resilience 59 , and which may be undermined by disturbances that cause topsoil erosion 60 . Moreover, as human disturbances intensify throughout the Amazon (Fig. 1 ), the spread of invasive grasses and fires can make the system increasingly homogeneous. Effects of heterogeneity on Amazon forest resilience have been poorly investigated so far (but see refs. 37 , 61 , 62 ) and many questions remain open, such as how much heterogeneity exists in the system and whether it can mitigate a systemic transition.

Sources of connectivity

Connectivity across Amazonian landscapes and regions can contribute to synchronize forest dynamics, causing different forests to behave more similarly 17 . Depending on the processes involved, connectivity can either increase or decrease the risk of systemic transition 17 . For instance, connectivity may facilitate forest recovery after disturbances through seed dispersal, but also it may spread disturbances, such as fire. In the Amazon, an important source of connectivity enhancing forest resilience is atmospheric moisture flow westward (Fig. 2 ), partly maintained by forest evapotranspiration 4 , 37 , 67 . Another example of connectivity that may increase social-ecological resilience is knowledge exchange among IPLCs about how to adapt to global change 68 , 69 (see Box 1 ). However, complex systems such as the Amazon can be particularly vulnerable to sources of connectivity that spread disturbances and increase the risk of systemic transition 70 . For instance, roads carving through the forest are well-known sources of illegal activities, such as logging and burning, which increase forest flammability 38 , 39 .

figure 2

Brazil holds 60% of the Amazon forest biome and has a major responsibility towards its neighbouring countries in the west. Brazil is the largest supplier of rainfall to western Amazonian countries. Up to one-third of the total annual rainfall in Amazonian territories of Bolivia, Peru, Colombia and Ecuador depends on water originating from Brazil’s portion of the Amazon forest. This international connectivity illustrates how policies related to deforestation, especially in the Brazilian Amazon, will affect the climate in other countries. Arrow widths are proportional to the percentage of the annual rainfall received by each country within their Amazonian areas. We only show flows with percentages higher than 10% (see  Methods for details).

Five critical drivers of water stress

Global warming.

Most CMIP6 models agree that a large-scale dieback of the Amazon is unlikely in response to global warming above pre-industrial levels 2 , but this ecosystem response is based on certain assumptions, such as a large CO 2 -fertilization effect 53 . Forests across the Amazon are already responding with increasing tree mortality rates that are not simulated by these models 46 , possibly because of compounding disturbance regimes (Fig. 1 ). Nonetheless, a few global climate models 3 , 14 , 71 , 72 , 73 , 74 indicate a broad range for a potential critical threshold in global warming between 2 and 6 °C (Fig. 3a ). These contrasting results can be explained by general differences between numerical models and their representation of the complex Amazonian system. While some models with dynamic vegetation indicate local-scale tipping events in peripheral parts of the Amazon 5 , 6 , other models suggest an increase in biomass and forest cover (for example, in refs. 53 , 54 ). For instance, a study found that when considering only climatic variability, a large-scale Amazon forest dieback is unlikely, even under a high greenhouse gas emission scenario 75 . However, most updated CMIP6 models agree that droughts in the Amazon region will increase in length and intensity, and that exceptionally hot droughts will become more common 2 , creating conditions that will probably boost other types of disturbances, such as large and destructive forest fires 76 , 77 . To avoid broad-scale ecosystem transitions due to synergies between climatic and land use disturbances (Fig. 3b ), we suggest a safe boundary for the Amazon forest at 1.5 °C for global warming above pre-industrial levels, in concert with the Paris Agreement goals.

figure 3

a , Five critical drivers of water stress on Amazonian forests affect (directly or indirectly) the underlying tipping point of the system. For each driver, we indicate potential critical thresholds and safe boundaries that define a safe operating space for keeping the Amazon forest resilient 11 , 12 . We followed the precautionary principle and considered the most conservative thresholds within the ranges, when confidence was low. b , Conceptual model showing how the five drivers may interact (arrows indicate positive effects) and how these interactions may strengthen a positive feedback between water stress and forest loss. These emerging positive feedback loops could accelerate a systemic transition of the Amazon forest 15 . At global scales, driver 1 (global warming) intensifies with greenhouse gas emissions, including emissions from deforestation. At local scales, driver 5 (accumulated deforestation) intensifies with land use changes. Drivers 2 to 4 (regional rainfall conditions) intensify in response to drivers 1 and 5. The intensification of these drivers may cause widespread tree mortality for instance because of extreme droughts and fires 76 . Water stress affects vegetation resilience globally 79 , 104 , but other stressors, such as heat stress 34 , 36 , may also have a role. In the coming decades, these five drivers could change at different rates, with some approaching a critical threshold faster than others. Therefore, monitoring them separately can provide vital information to guide mitigation and adaptation strategies.

Annual rainfall

Satellite observations of tree cover distributions across tropical South America suggest a critical threshold between 1,000 and 1,250 mm of annual rainfall 78 , 79 . On the basis of our reanalysis using tree cover data from the Amazon basin (Extended Data Fig. 1a ), we confirm a potential threshold at 1,000 mm of annual rainfall (Fig. 3a ), below which forests become rare and unstable. Between 1,000 and 1,800 mm of annual rainfall, high and low tree cover ecosystems exist in the Amazon as two alternative stable states (see Extended Data Table 2 for uncertainty ranges). Within the bistability range in annual rainfall conditions, forests are relatively more likely to collapse when severely disturbed, when compared to forests in areas with annual rainfall above 1,800 mm (Extended Data Fig. 1a ). For floodplain ecosystems covering 14% of the forest biome, a different critical threshold has been estimated at 1,500 mm of annual rainfall 65 , implying that floodplain forests may be the first to collapse in a drier future. To avoid local-scale ecosystem transitions due to compounding disturbances, we suggest a safe boundary in annual rainfall conditions at 1,800 mm.

Rainfall seasonality intensity

Satellite observations of tree cover distributions across tropical South America suggest a critical threshold in rainfall seasonality intensity at −400 mm of the maximum cumulative water deficit 37 , 80 (MCWD). Our reanalysis of the Amazon basin (Extended Data Fig. 1c ) confirms the critical threshold at approximately −450 mm in the MCWD (Fig. 3a ), and suggests a bistability range between approximately −350 and −450 mm (see Extended Data Table 2 for uncertainty ranges), in which forests are more likely to collapse when severely disturbed than forests in areas with MCWD below −350 mm. To avoid local-scale ecosystem transitions due to compounding disturbances, we suggest a safe boundary of MCWD at −350 mm.

Dry season length

Satellite observations of tree cover distributions across tropical South America suggest a critical threshold at 7 months of dry season length 79 (DSL). Our reanalysis of the Amazon basin (Extended Data Fig. 1d ) suggests a critical threshold at eight months of DSL (Fig. 3a ), with a bistability range between approximately five and eight months (see Extended Data Table 2 for uncertainty ranges), in which forests are more likely to collapse when severely disturbed than forests in areas with DSL below five months. To avoid local-scale ecosystem transitions due to compounding disturbances, we suggest a safe boundary of DSL at five months.

Accumulated deforestation

A potential vegetation model 81 found a critical threshold at 20% of accumulated deforestation (Fig. 3a ) by simulating Amazon forest responses to different scenarios of accumulated deforestation (with associated fire events) and of greenhouse gas emissions, and by considering a CO 2 fertilization effect of 25% of the maximum photosynthetic assimilation rate. Beyond 20% deforestation, forest mortality accelerated, causing large reductions in regional rainfall and consequently an ecosystem transition of 50−60% of the Amazon, depending on the emissions scenario. Another study using a climate-vegetation model found that with accumulated deforestation of 30−50%, rainfall in non-deforested areas downwind would decline 67 by 40% (ref.  67 ), potentially causing more forest loss 4 , 37 . Other more recent models incorporating fire disturbances support a potential broad-scale transition of the Amazon forest, simulating a biomass loss of 30–40% under a high-emission scenario 5 , 82 (SSP5–8.5 at 4 °C). The Amazon biome has already lost 13% of its original forest area due to deforestation 83 (or 15% of the biome if we consider also young secondary forests 83 that provide limited contribution to moisture flow 84 ). Among the remaining old-growth forests, at least 38% have been degraded by land use disturbances and repeated extreme droughts 39 , with impacts on moisture recycling that are still uncertain. Therefore, to avoid broad-scale ecosystem transitions due to runaway forest loss (Fig. 3b ), we suggest a safe boundary of accumulated deforestation of 10% of the original forest biome cover, which requires ending large-scale deforestation and restoring at least 5% of the biome.

Three alternative ecosystem trajectories

Degraded forest.

In stable forest regions of the Amazon with annual rainfall above 1,800 mm (Extended Data Fig. 1b ), forest cover usually recovers within a few years or decades after disturbances, yet forest composition and functioning may remain degraded for decades or centuries 84 , 85 , 86 , 87 . Estimates from across the Amazon indicate that approximately 30% of areas previously deforested are in a secondary forest state 83 (covering 4% of the biome). An additional 38% of the forest biome has been damaged by extreme droughts, fires, logging and edge effects 38 , 39 . These forests may naturally regrow through forest succession, yet because of feedbacks 15 , succession can become arrested, keeping forests persistently degraded (Fig. 4 ). Different types of degraded forests have been identified in the Amazon, each one associated with a particular group of dominant opportunistic plants. For instance, Vismia forests are common in old abandoned pastures managed with fire 85 , and are relatively stable, because Vismia trees favour recruitment of Vismia seedlings in detriment of other tree species 88 , 89 . Liana forests can also be relatively stable, because lianas self-perpetuate by causing physical damage to trees, allowing lianas to remain at high density 90 , 91 . Liana forests are expected to expand with increasing aridity, disturbance regimes and CO 2 fertilization 90 . Guadua bamboo forests are common in the southwestern Amazon 92 , 93 . Similar to lianas, bamboos self-perpetuate by causing physical damage to trees and have been expanding over burnt forests in the region 92 . Degraded forests are usually dominated by native opportunistic species, and their increasing expansion over disturbed forests could affect Amazonian functioning and resilience in the future.

figure 4

From examples of disturbed forests across the Amazon, we identify the three most plausible ecosystem trajectories related to the types of disturbances, feedbacks and local environmental conditions. These alternative trajectories may be irreversible or transient depending on the strength of the novel interactions 15 . Particular combinations of interactions (arrows show positive effects described in the literature) may form feedback loops 15 that propel the ecosystem through these trajectories. In the ‘degraded forest’ trajectory, feedbacks often involve competition between trees and other opportunistic plants 85 , 90 , 92 , as well as interactions between deforestation, fire and seed limitation 84 , 87 , 105 . At the landscape scale, secondary forests are more likely to be cleared than mature forests, thus keeping forests persistently young and landscapes fragmented 83 . In the ‘degraded open-canopy ecosystem’ trajectory, feedbacks involve interactions among low tree cover and fire 97 , soil erosion 60 , seed limitation 105 , invasive grasses and opportunistic plants 96 . At the regional scale, a self-reinforcing feedback between forest loss and reduced atmospheric moisture flow may increase the resilience of these open-canopy degraded ecosystems 42 . In the ‘white-sand savanna’ trajectory, the main feedbacks result from interactions among low tree cover and fire, soil erosion, and seed limitation 106 . Bottom left, floodplain forest transition to white-sand savanna after repeated fires (photo credit: Bernardo Flores); bottom centre, forest transition to degraded open-canopy ecosystem after repeated fires (photo credit: Paulo Brando); bottom right, forest transition to Vismia degraded forest after slash-and-burn agriculture (photo credit: Catarina Jakovac).

White-sand savanna

White-sand savannas are ancient ecosystems that occur in patches within the Amazon forest biome, particularly in seasonally waterlogged or flooded areas 94 . Their origin has been attributed to geomorphological dynamics and past Indigenous fires 26 , 27 , 94 . In a remote landscape far from large agricultural frontiers, within a stable forest region of the Amazon (Extended Data Fig. 1b ), satellite and field evidence revealed that white-sand savannas are expanding where floodplain forests were repeatedly disturbed by fires 95 . After fire, the topsoil of burnt forests changes from clayey to sandy, favouring the establishment of savanna trees and native herbaceous plants 95 . Shifts from forest to white-sand savanna (Fig. 4 ) are probably stable (that is, the ecosystem is unlikely to recover back to forest within centuries), based on the relatively long persistence of these savannas in the landscape 94 . Although these ecosystem transitions have been confirmed only in the Negro river basin (central Amazon), floodplain forests in other parts of the Amazon were shown to be particularly vulnerable to collapse 45 , 64 , 65 .

Degraded open-canopy ecosystem

In bistable regions of the Amazon forest with annual rainfall below 1,800 mm (Extended Data Fig. 1b ), shifts to degraded open-canopy ecosystems are relatively common after repeated disturbances by fire 45 , 96 . The ecosystem often becomes dominated by fire-tolerant tree and palm species, together with alien invasive grasses and opportunistic herbaceous plants 96 , 97 , such as vines and ferns. Estimates from the southern Amazon indicate that 5−6% of the landscape has already shifted into degraded open-canopy ecosystems due to deforestation and fires 45 , 96 . It is still unclear, however, whether degraded open-canopy ecosystems are stable or transient (Fig. 4 ). Palaeorecords from the northern Amazon 98 show that burnt forests may spend centuries in a degraded open-canopy state before they eventually shift into a savanna. Today, invasion by alien flammable grasses is a novel stabilizing mechanism 96 , 97 , but the long-term persistence of these grasses in the ecosystem is also uncertain.

Prospects for modelling Amazon forest dynamics

Several aspects of the Amazon forest system may help improve earth system models (ESMs) to more accurately simulate ecosystem dynamics and feedbacks with the climate system. Simulating individual trees can improve the representation of growth and mortality dynamics, which ultimately affect forest dynamics (for example, refs. 61 , 62 , 99 ). Significant effects on simulation results may emerge from increasing plant functional diversity, representation of key physiological trade-offs and other features that determine water stress on plants, and also allowing for community adjustment to environmental heterogeneity and global change 32 , 55 , 62 , 99 . For now, most ESMs do not simulate a dynamic vegetation cover (Supplementary Table 1 ) and biomes are represented based on few plant functional types, basically simulating monocultures on the biome level. In reality, tree community adaptation to a heterogenous and dynamic environment feeds into the whole-system dynamics, and not covering such aspects makes a true Amazon tipping assessment more challenging.

Our findings also indicate that Amazon forest resilience is affected by compounding disturbances (Fig. 1 ). ESMs need to include different disturbance scenarios and potential synergies for creating more realistic patterns of disturbance regimes. For instance, logging and edge effects can make a forest patch more flammable 39 , but these disturbances are often not captured by ESMs. Improvements in the ability of ESMs to predict future climatic conditions are also required. One way is to identify emergent constraints 100 , lowering ESMs variations in their projections of the Amazonian climate. Also, fully coupled ESMs simulations are needed to allow estimates of land-atmosphere feedbacks, which may adjust climatic and ecosystem responses. Another way to improve our understanding of the critical thresholds for Amazonian resilience and how these link to climatic conditions and to greenhouse gas concentrations is through factorial simulations with ESMs. In sum, although our study may not deliver a set of reliable and comprehensive equations to parameterize processes impacting Amazon forest dynamics, required for implementation in ESMs, we highlight many of the missing modelled processes.

Implications for governance

Forest resilience is changing across the Amazon as disturbance regimes intensify (Fig. 1 ). Although most recent models agree that a large-scale collapse of the Amazon forest is unlikely within the twenty-first century 2 , our findings suggest that interactions and synergies among different disturbances (for example, frequent extreme hot droughts and forest fires) could trigger unexpected ecosystem transitions even in remote and central parts of the system 101 . In 2012, Davidson et al. 102 demonstrated how the Amazon basin was experiencing a transition to a ‘disturbance-dominated regime’ related to climatic and land use changes, even though at the time, annual deforestation rates were declining owing to new forms of governance 103 . Recent policy and approaches to Amazon development, however, accelerated deforestation that reached 13,000 km 2 in the Brazilian Amazon in 2021 ( http://terrabrasilis.dpi.inpe.br ). The southeastern region has already turned into a source of greenhouse gases to the atmosphere 48 . The consequences of losing the Amazon forest, or even parts of it, imply that we must follow a precautionary approach—that is, we must take actions that contribute to maintain the Amazon forest within safe boundaries 12 . Keeping the Amazon forest resilient depends firstly on humanity’s ability to stop greenhouse gas emissions, mitigating the impacts of global warming on regional climatic conditions 2 . At the local scale, two practical and effective actions need to be addressed to reinforce forest–rainfall feedbacks that are crucial for the resilience of the Amazon forest 4 , 37 : (1) ending deforestation and forest degradation; and (2) promoting forest restoration in degraded areas. Expanding protected areas and Indigenous territories can largely contribute to these actions. Our findings suggest a list of thresholds, disturbances and feedbacks that, if well managed, can help maintain the Amazon forest within a safe operating space for future generations.

Our study site was the area of the Amazon basin, considering large areas of tropical savanna biome along the northern portion of the Brazilian Cerrado, the Gran Savana in Venezuela and the Llanos de Moxos in Bolivia, as well as the Orinoco basin to the north, and eastern parts of the Andes to the west. The area includes also high Andean landscapes with puna and paramo ecosystems. We chose this contour to allow better communication with the MapBiomas Amazonian Project (2022; https://amazonia.mapbiomas.org ). For specific interpretation of our results, we considered the contour of the current extension of the Amazon forest biome, which excludes surrounding tropical savanna biomes.

We used the Moderate Resolution Imaging Spectroradiometer (MODIS) Vegetation Continuous Fields (VCF) data (MOD44B version 6; https://lpdaac.usgs.gov/products/mod44bv006/ ) for the year 2001 at 250-m resolution 124 to reanalyse tree cover distributions within the Amazon basin, refining estimates of bistability ranges and critical thresholds in rainfall conditions from previous studies. Although MODIS VCF can contain errors within lower tree cover ranges and should not be used to test for bistability between grasslands and savannas 125 , the dataset is relatively robust for assessing bistability within the tree cover range of forests and savannas 126 , as also shown by low uncertainty (standard deviation of tree cover estimates) across the Amazon (Extended Data Fig. 8 ).

We used the Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS; https://www.chc.ucsb.edu/data/chirps ) 127 to estimate mean annual rainfall and rainfall seasonality for the present across the Amazon basin, based on monthly means from 1981 to 2020, at a 0.05° spatial resolution.

We used the Climatic Research Unit (CRU; https://www.uea.ac.uk/groups-and-centres/climatic-research-unit ) 128 to estimate mean annual temperature for the present across the Amazon basin, based on monthly means from 1981 to 2020, at a 0.5° spatial resolution.

To mask deforested areas until 2020, we used information from the MapBiomas Amazonia Project (2022), collection 3, of Amazonian Annual Land Cover and Land Use Map Series ( https://amazonia.mapbiomas.org ).

To assess forest fire distribution across the Amazon forest biome and in relation to road networks, we used burnt area fire data obtained from the AQUA sensor onboard the MODIS satellite. Only active fires with a confidence level of 80% or higher were selected. The data are derived from MODIS MCD14ML (collection 6) 129 , available in Fire Information for Resource Management System (FIRMS). The data were adjusted to a spatial resolution of 1 km.

Potential analysis

Using potential analysis 130 , an empirical stability landscape was constructed based on spatial distributions of tree cover (excluding areas deforested until 2020; https://amazonia.mapbiomas.org ) against mean annual precipitation, MCWD and DSL. Here we followed the methodology of Hirota et al. 104 . For bins of each of the variables, the probability density of tree cover was determined using the MATLAB function ksdensity. Local maxima of the resulting probability density function are considered to be stable equilibria, in which local maxima below a threshold value of 0.005 were ignored. Based on sensitivity tests (see below), we chose the intermediate values of the sensitivity parameter for each analysis, which resulted in the critical thresholds most similar to the ones previously published in the literature.

Sensitivity tests of the potential analysis

We smoothed the densities of tree cover with the MATLAB kernel smoothing function ksdensity. Following Hirota et al. 104 , we used a flexible bandwidth ( h ) according to Silverman’s rule of thumb 131 : h  = 1.06 σn 1/5 , where σ is the standard deviation of the tree cover distribution and n is the number of points. To ignore small bumps in the frequency distributions, we used a dimensionless sensitivity parameter. This parameter filters out weak modes in the distributions such that a higher value implies a stricter criterion to detect a significant mode. In the manuscript, we used a value of 0.005. For different values of this sensitivity parameter, we here test the estimated critical thresholds and bistability ranges (Extended Data Table 2 ). We inferred stable and unstable states of tree cover (minima and maxima in the potentials) for moving windows of the climatic variables. For mean annual precipitation, we used increments of 10 mm yr −1 between 0 and 3500 mm yr −1 . For dry season length, we used increments of 0.1 months between 0 and 12 months. For MCWD, we used increments of 10 mm between −800 mm and 0 mm.

Transition potential

We quantified a relative ecosystem transition potential across the Amazon forest biome (excluding accumulated deforestation; https://amazonia.mapbiomas.org ) to produce a simple spatial measure that can be useful for governance. For this, we combined information per pixel, at 5 km resolution, about different disturbances related to climatic and human disturbances, as well as high-governance areas within protected areas and Indigenous territories. We used values of significant slopes of the dry season (July–October) mean temperature between 1981 and 2020 ( P  < 0.1), estimated using simple linear regressions (at 0.5° resolution from CRU) (Fig. 1a ). Ecosystem stability classes (stable forest, bistable and stable savanna as in Extended Data Fig. 1 ) were estimated using simple linear regression slopes of annual rainfall between 1981 and 2020 ( P  < 0.1) (at 0.05° resolution from CHIRPS), which we extrapolated to 2050 (Fig. 1b and Extended Data Fig. 3 ). Distribution of areas affected by repeated extreme drought events (Fig. 1c ) were defined when the time series (2001–2018) of the MCWD reached two standard deviation anomalies from historical mean. Extreme droughts were obtained from Lapola et al. 39 , based on Climatic Research Unit gridded Time Series (CRU TS 4.0) datasets for precipitation and evapotranspiration. The network of roads (paved and unpaved) across the Amazon forest biome (Fig. 1d ) was obtained from the Amazon Network of Georeferenced Socio-Environmental Information (RAISG; https://geo2.socioambiental.org/raisg ). Protected areas (PAs) and Indigenous territories (Fig. 1e ) were also obtained from RAISG, and include both sustainable-use and restricted-use protected areas managed by national or sub-national governments, together with officially recognized and proposed Indigenous territories. We combined these different disturbance layers by adding a value for each layer in the following way: (1) slopes of dry season temperature change (as in Fig. 1a , multiplied by 10, thus between −0.1 and +0.6); (2) ecosystem stability classes estimated for year 2050 (as in Fig. 1b ), with 0 for stable forest, +1 for bistable and +2 for stable savanna; (3) accumulated impacts from repeated extreme drought events (from 0 to 5 events), with +0.2 for each event; (4) road-related human impacts, with +1 for pixels within 10 km from a road; and (5) protected areas and Indigenous territories as areas with lower exposure to human (land use) disturbances, such as deforestation and forest fires, with −1 for pixels inside these areas. The sum of these layers revealed relative spatial variation in ecosystem transition potential by 2050 across the Amazon (Fig. 1f ), ranging from −1 (low potential) to 4 (very high potential).

Atmospheric moisture tracking

To determine the atmospheric moisture flows between the Amazonian countries, we use the Lagrangian atmospheric moisture tracking model UTrack 132 . The model tracks the atmospheric trajectories of parcels of moisture, updates their coordinates at each time step of 0.1 h and allocates moisture to a target location in case of precipitation. For each millimetre of evapotranspiration, 100 parcels are released into the atmosphere. Their trajectories are forced with evaporation, precipitation, and wind speed estimates from the ERA5 reanalysis product at 0.25° horizontal resolution for 25 atmospheric layers 133 . Here we use the runs from Tuinenburg et al. 134 , who published monthly climatological mean (2008–2017) moisture flows between each pair of 0.5° grid cells on Earth. We aggregated these monthly flows, resulting in mean annual moisture flows between all Amazonian countries during 2008–2017. For more details of the model runs, we refer to Tuinenburg and Staal 132 and Tuinenburg et al. 134 .

Reporting summary

Further information on research design is available in the  Nature Portfolio Reporting Summary linked to this article.

Data availability

All data supporting the findings of this study are openly available and their sources are presented in the Methods.

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Acknowledgements

This work was inspired by the Science Panel for the Amazon (SPA) initiative ( https://www.theamazonwewant.org/ ) that produced the first Amazon Assessment Report (2021). The authors thank C. Smith for providing deforestation rates data used in Extended Data Fig. 5b . B.M.F. and M.H. were supported by Instituto Serrapilheira (Serra-1709-18983) and C.J. (R-2111-40341). A.S. acknowledges funding from the Dutch Research Council (NWO) under the Talent Program Grant VI.Veni.202.170. R.A.B. and D.M.L. were supported by the AmazonFACE programme funded by the UK Foreign, Commonwealth and Development Office (FCDO) and Brazilian Ministry of Science, Technology and Innovation (MCTI). R.A.B. was additionally supported by the Met Office Climate Science for Service Partnership (CSSP) Brazil project funded by the UK Department for Science, Innovation and Technology (DSIT), and D.M.L. was additionally supported by FAPESP (grant no. 2020/08940-6) and CNPq (grant no. 309074/2021-5). C.L. thanks CNPq (proc. 159440/2018-1 and 400369/2021-4) and Brazil LAB (Princeton University) for postdoctoral fellowships. A.E.-M. is supported by the UKRI TreeScapes MEMBRA (NE/V021346/1), the Royal Society (RGS\R1\221115), the ERC TreeMort project (758873) and the CESAB Syntreesys project. R.S.O. received a CNPq productivity scholarship and funding from NERC-FAPESP 2019/07773-1. S.B.H. is supported by the Geneva Graduate Institute research funds, and UCLA’s committee on research. J.A.M. is supported by the National Institute of Science and Technology for Climate Change Phase 2 under CNPq grant 465501/2014-1; FAPESP grants 2014/50848-9, the National Coordination for Higher Education and Training (CAPES) grant 88887.136402-00INCT. L.S.B. received FAPESP grant 2013/50531-0. D.N. and N.B. acknowledge funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 820970. N.B. has received further funding from the Volkswagen foundation, the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 956170, as well as from the German Federal Ministry of Education and Research under grant no. 01LS2001A.

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Authors and affiliations.

Graduate Program in Ecology, Federal University of Santa Catarina, Florianopolis, Brazil

Bernardo M. Flores, Carolina Levis & Marina Hirota

Geosciences Barcelona, Spanish National Research Council, Barcelona, Spain

Encarni Montoya

Potsdam Institute for Climate Impact Research, Member of the Leibniz Association, Potsdam, Germany

Boris Sakschewski, Da Nian & Niklas Boers

Institute of Advanced Studies, University of São Paulo, São Paulo, Brazil

Nathália Nascimento & Carlos A. Nobre

Copernicus Institute of Sustainable Development, Utrecht University, Utrecht, The Netherlands

Met Office Hadley Centre, Exeter, UK

Richard A. Betts

Global Systems Institute, University of Exeter, Exeter, UK

Center for Meteorological and Climatic Research Applied to Agriculture, University of Campinas, Campinas, Brazil

David M. Lapola

School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK

Adriane Esquível-Muelbert

Birmingham Institute of Forest Research, University of Birmingham, Birmingham, UK

Department of Plant Sciences, Federal University of Santa Catarina, Florianopolis, Brazil

Catarina Jakovac

Department of Plant Biology, University of Campinas, Campinas, Brazil

Rafael S. Oliveira & Marina Hirota

Division of Impacts, Adaptation and Vulnerabilities (DIIAV), National Institute for Space Research, São José dos Campos, Brazil

Laura S. Borma & Luciana V. Gatti

Earth System Modelling, School of Engineering and Design, Technical University of Munich, Munich, Germany

Niklas Boers

Luskin School for Public Affairs and Institute of the Environment, University of California, Los Angeles, CA, USA

Susanna B. Hecht

Naturalis Biodiversity Center, Leiden, The Netherlands

Hans ter Steege

Quantitative Biodiversity Dynamics, Utrecht University, Utrecht, The Netherlands

Science Panel for the Amazon (SPA), São José dos Campos, Brazil

Julia Arieira

Sustainable Development Solutions Network, New York, NY, USA

Isabella L. Lucas

Environmental Change Institute, University of Oxford, Oxford, UK

Erika Berenguer

Centro Nacional de Monitoramento e Alerta de Desastres Naturais, São José dos Campos, Brazil

José A. Marengo

Graduate Program in Natural Disasters, UNESP/CEMADEN, São José dos Campos, Brazil

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Caio R. C. Mattos

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Contributions

B.M.F. and M.H. conceived the study. B.M.F. reviewed the literature, with inputs from all authors. B.M.F., M.H., N.N., A.S., C.L., D.N, H.t.S. and C.R.C.M. assembled datasets. M.H. analysed temperature and rainfall trends. B.M.F. and N.N. produced the maps in main figures and calculated transition potential. A.S. performed potential analysis and atmospheric moisture tracking. B.M.F. produced the figures and wrote the manuscript, with substantial inputs from all authors. B.S. wrote the first version of the ‘Prospects for modelling Amazon forest dynamics’ section, with inputs from B.M.F and M.H.

Corresponding authors

Correspondence to Bernardo M. Flores or Marina Hirota .

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Extended data figures and tables

Extended data fig. 1 alternative stable states in amazonian tree cover relative to rainfall conditions..

Potential analysis of tree cover distributions across rainfall gradients in the Amazon basin suggest the existence of critical thresholds and alternative stable states in the system. For this, we excluded accumulated deforestation until 2020 and included large areas of tropical savanna biome in the periphery of the Amazon basin (see  Methods ). Solid black lines indicate two stable equilibria. Small grey arrows indicate the direction towards equilibrium. (a) The overlap between ~ 1,000 and 1,800 mm of annual rainfall suggests that two alternative stable states may exist (bistability): a high tree cover state ~ 80 % (forests), and a low tree cover state ~ 20% (savannas). Tree cover around 50 % is rare, indicating an unstable state. Below 1,000 mm of annual rainfall, forests are rare, indicating a potential critical threshold for abrupt forest transition into a low tree cover state 79 , 104 (arrow 1). Between 1,000 and 1,800 mm of annual rainfall, the existence of alternative stable states implies that forests can shift to a low tree cover stable state in response to disturbances (arrow 2). Above 1,800 mm of annual rainfall, low tree cover becomes rare, indicating a potential critical threshold for an abrupt transition into a high tree cover state. In this stable forest state, forests are expected to always recover after disturbances (arrow 3), although composition may change 47 , 85 . (b) Currently, the stable savanna state covers 1 % of the Amazon forest biome, bistable areas cover 13 % of the biome (less than previous analysis using broader geographical ranges 78 ) and the stable forest state covers 86 % of the biome. Similar analyses using the maximum cumulative water deficit (c) and the dry season length (d) also suggest the existence of critical thresholds and alternative stable states. When combined, these critical thresholds in rainfall conditions could result in a tipping point of the Amazon forest in terms of water stress, but other factors may play a role, such as groundwater availability 64 . MODIS VCF may contain some level of uncertainty for low tree cover values, as shown by the standard deviation of tree cover estimates across the Amazon (Extended Data Fig. 8 ). However, the dataset is relatively robust for assessing bistability within the tree cover range between forest and savanna 126 .

Extended Data Fig. 2 Changes in dry-season temperatures across the Amazon basin.

(a) Dry season temperature averaged from mean annual data observed between 1981 and 2010. (b) Changes in dry season mean temperature based on the difference between the projected future (2021−2050) and observed historical (1981−2010) climatologies. Future climatology was obtained from the estimated slopes using historical CRU data 128 (shown in Fig. 1a ). (c, d) Changes in the distributions of dry season mean and maximum temperatures for the Amazon basin. (e) Correlation between dry-season mean and maximum temperatures observed (1981–2010) across the Amazon basin ( r  = 0.95).

Extended Data Fig. 3 Changes in annual precipitation and ecosystem stability across the Amazon forest biome.

(a) Slopes of annual rainfall change between 1981 and 2020 estimated using simple regressions (only areas with significant slopes, p  < 0.1). (b) Changes in ecosystem stability classes projected for year 2050, based on significant slopes in (a) and critical thresholds in annual rainfall conditions estimated in Extended Data Fig. 1 . Data obtained from Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS), at 0.05° spatial resolution 127 .

Extended Data Fig. 4 Changes in ecosystem stability by 2050 across the Amazon based on annual rainfall projected by CMIP6 models.

(a) Changes in stability classes estimated using an ensemble with the five CMIP6 models that include vegetation modules (coupled for climate-vegetation feedbacks) for two emission scenarios (Shared Socio-economic Pathways - SSPs). (b) Changes in stability classes estimated using an ensemble with all 33 CMIP6 models for the same emission scenarios. Stability changes may occur between stable forest (F), stable savanna (S) and bistable (B) classes, based on the bistability range of 1,000 – 1,800 mm in annual rainfall, estimated from current rainfall conditions (see Extended Data Fig. 1 ). Projections are based on climate models from the 6 th Phase of the Coupled Model Intercomparison Project (CMIP6). SSP2-4.5 is a low-emission scenario of future global warming and SSP5-8.5 is a high-emission scenario. The five coupled models analysed separately in (a) were: EC-Earth3-Veg, GFDL-ESM4, MPI-ESM1-2-LR, TaiESM1 and UKESM1-0-LL (Supplementary Information Table 1 ).

Extended Data Fig. 5 Deforestation continues to expand within the Amazon forest system.

(a) Map highlighting deforestation and fire activity between 2012 and 2021, a period when environmental governance began to weaken again, as indicated by increasing rates of annual deforestation in (b). In (b), annual deforestation rates for the entire Amazon biome were adapted with permission from Smith et al. 83 .

Extended Data Fig. 6 Environmental heterogeneity in the Amazon forest system.

Heterogeneity involves myriad factors, but two in particular, related to water availability, were shown to contribute to landscape-scale heterogeneity in forest resilience; topography shapes fine-scale variations of forest drought-tolerance 135 , 136 , and floodplains may reduce forest resilience by increasing vulnerability to wildfires 65 . Datasets: topography is shown by the Shuttle Radar Topography Mission (SRTM; https://earthexplorer.usgs.gov/ ) 137 at 90 m resolution; floodplains and uplands are separated with the Amazon wetlands mask 138 at 90 m resolution.

Extended Data Fig. 7 The Amazon is biologically and culturally diverse.

(a) Tree species richness and (b) language richness illustrate how biological and cultural diversity varies across the Amazon. Diverse tree communities and human cultures contribute to increasing forest resilience in various ways that are being undermined by land-use and climatic changes. Datasets: (a) Amazon Tree Diversity Network (ATDN, https://atdn.myspecies.info ). (b) World Language Mapping System (WLMS) obtained under license from Ethnologue 139 .

Extended Data Fig. 8 Uncertainty of the MODIS VCF dataset across the Amazon basin.

Map shows standard deviation (SD) of tree cover estimates from MODIS VCF 124 . We masked deforested areas until 2020 using the MapBiomas Amazonia Project (2022; https://amazonia.mapbiomas.org ).

Supplementary information

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Flores, B.M., Montoya, E., Sakschewski, B. et al. Critical transitions in the Amazon forest system. Nature 626 , 555–564 (2024). https://doi.org/10.1038/s41586-023-06970-0

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  • Largest Covid Vaccine Study Yet Finds Links to Health Conditions

(Bloomberg) -- Vaccines that protect against severe illness, death and lingering long Covid symptoms from a coronavirus infection were linked to small increases in neurological, blood, and heart-related conditions in the largest global vaccine safety study to date.

The rare events — identified early in the pandemic — included a higher risk of heart-related inflammation from mRNA shots made by Pfizer Inc., BioNTech SE, and Moderna Inc., and an increased risk of a type of blood clot in the brain after immunization with viral-vector vaccines such as the one developed by the University of Oxford and made by AstraZeneca Plc. 

The viral-vector jabs were also tied to an increased risk of Guillain-Barre syndrome , a neurological disorder in which the immune system mistakenly attacks the peripheral nervous system.

More than 13.5 billion doses of Covid vaccines have been administered globally over the past three years, saving over 1 million lives in Europe alone. Still, a small proportion of people immunized were injured by the shots, stoking debate about their benefits versus harms.

The new research, by the Global Vaccine Data Network, was published in the journal Vaccine last week, with the data made available via interactive dashboards to show methodology and specific findings. 

Read More: Covid Test Failures Highlight Evolving Relationship With Virus

The research looked for 13 medical conditions that the group considered “adverse events of special interest” among 99 million vaccinated individuals in eight countries, aiming to identify higher-than-expected cases after a Covid shot. The use of aggregated data increased the possibility of identifying rare safety signals that might have been missed when looking only at smaller populations.

Myocarditis , or inflammation of the heart muscle, was consistently identified following a first, second and third dose of mRNA vaccines, the study found. The highest increase in the observed-to-expected ratio was seen after a second jab with the Moderna shot. A first and fourth dose of the same vaccine was also tied to an increase in pericarditis, or inflammation of the thin sac covering the heart. 

Safety Signals

Researchers found a statistically significant increase in cases of Guillain-Barre syndrome within 42 days of an initial Oxford-developed ChAdOx1 or “Vaxzevria” shot that wasn’t observed with mRNA vaccines. Based on the background incidence of the condition, 66 cases were expected — but 190 events were observed. 

ChAdOx1 was linked to a threefold increase in cerebral venous sinus thrombosis, a type of blood clot in the brain, identified in 69 events, compared with an expected 21. The small risk led to the vaccine’s withdrawal or restriction in Denmark and multiple other countries. Myocarditis was also linked to a third dose of ChAdOx1 in some, but not all, populations studied.

Possible safety signals for transverse myelitis — spinal cord inflammation — after viral-vector vaccines were identified in the study. So was acute disseminated encephalomyelitis — inflammation and swelling in the brain and spinal cord — after both viral-vector and mRNA vaccines. 

Listen to the  Big Take  podcast on  iHeart ,  Apple Podcasts ,  Spotify  and the Bloomberg Terminal.  Read the transcript .

Seven cases of acute disseminated encephalomyelitis after vaccination with the Pfizer-BioNTech vaccine were observed, versus an expectation of two.  

The adverse events of special interest were selected based on pre-established associations with immunization, what was already known about immune-related conditions and pre-clinical research. The study didn’t monitor for postural orthostatic tachycardia syndrome , or POTS, that some research has linked with Covid vaccines.

Exercise intolerance, excessive fatigue, numbness and “brain fog” were among common symptoms identified in more than 240 adults experiencing chronic post-vaccination syndrome in a separate study conducted by the Yale School of Medicine. The cause of the syndrome isn’t yet known, and it has no diagnostic tests or proven remedies.

Read More: Strenuous Exercise May Harm Long Covid Sufferers, Study Shows

The Yale research aims to understand the condition to relieve the suffering of those affected and improve the safety of vaccines, said Harlan Krumholz, a principal investigator of the study, and director of the Yale New Haven Hospital Center for Outcomes Research and Evaluation. 

Read this next :  Why Driving a Few Miles Can Save Patients a Fortune on Health Care

“Both things can be true,” Krumholz said in an interview. “They can save millions of lives, and there can be a small number of people who’ve been adversely affected.” 

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The Cases Against Trump: A Guide

Fraud. Hush money. Election subversion. Mar-a-Lago documents. One place to keep track of the presidential candidate’s legal troubles.

Arrows pointing at Donald Trump

Not long ago, the idea that a former president—or major-party presidential nominee—would face serious legal jeopardy was nearly unthinkable. Today, merely keeping track of the many cases against Donald Trump requires a law degree, a great deal of attention, or both.

In all, Trump faces 91 felony counts across two state courts and two different federal districts, any of which could potentially produce a prison sentence. He’s also dealing with a civil suit in New York that could force drastic changes to his business empire, including closing down its operations in his home state. Meanwhile, he is the leading Republican candidate in the race to become the next president—though the Supreme Court has now heard a case seeking to disqualify him. If the criminal and civil cases unfold with any reasonable timeliness, he could be in the heat of the campaign at the same time that his legal fate is being decided.

David A. Graham: The end of Trump Inc.

Here’s a summary of the major legal cases against Trump, including key dates, an assessment of the gravity of the charges, and expectations about how they could turn out. This guide will be updated regularly as the cases proceed.

New York State: Fraud

In the fall of 2022, New York Attorney General Letitia James filed a civil suit against Trump, his adult sons, and his former aide Allen Weisselberg, alleging a years-long scheme in which Trump fraudulently reported the value of properties in order to either lower his tax bill or improve the terms of his loans, all with an eye toward inflating his net worth.

When? Justice Arthur Engoron ruled against Trump and his co-defendants in late September 2023, concluding that many of the defendants’ claims were “clearly” fraudulent—so clearly that he didn’t need a trial to hear them. (He also sanctioned Trump’s lawyers for making repeated frivolous arguments.) Engoron has also fined Trump a total of $15,000 for violating a gag order in the case. The trial ended in January, and a ruling is currently expected in mid-February .

How grave is the allegation? Fraud is fraud, and in this case, the sum of the fraud stretched into the millions—but compared with some of the other legal matters in which Trump is embroiled, this is pretty pedestrian. The case is also civil rather than criminal. But although the stakes are lower for the nation, they remain high for Trump: Engoron could bar Trump’s famed company from business in New York, strip it of several key properties, and fine Trump hundreds of millions of dollars.

How plausible is a guilty verdict? Engoron has already ruled that Trump committed fraud. The outstanding questions are what damages he might have to pay and what exactly Engoron’s ruling means for Trump’s business and properties in New York.

Manhattan: Defamation and Sexual Assault

Although these other cases are all brought by government entities, Trump also faced a pair of defamation suits from the writer E. Jean Carroll, who said that Trump sexually assaulted her in a department-store dressing room in the 1990s. When he denied it, she sued him for defamation and later added a battery claim.

When? In May 2023, a jury concluded that Trump had sexually assaulted and defamed Carroll, and awarded her $5 million. A second defamation case produced an $83.3 million judgment in January 2024.

How grave was the allegation? Although these cases don’t directly connect to the same fundamental issues of rule of law and democratic governance that some of the criminal cases do, they were a serious matter, and a federal judge’s blunt statement that Trump raped Carroll has gone underappreciated.

What happens now? Trump has appealed both cases. During the second trial, he also continued to insult Carroll, which may have courted additional defamation suits.

Manhattan: Hush Money

In March 2023, Manhattan District Attorney Alvin Bragg became the first prosecutor to bring felony charges against Trump, alleging that the former president falsified business records as part of a scheme to pay hush money to women who said they had had sexual relationships with Trump.

When? The case is set to go to trial on March 25, Judge Juan Merchant said on February 15.

How grave is the allegation? Falsifying records is a crime, and crime is bad. But many people have analogized this case to Al Capone’s conviction on tax evasion: It’s not that he didn’t deserve it, but it wasn’t really why he was an infamous villain. That this case alleges behavior that didn’t directly attack elections or put national secrets at risk makes it feel more minor—in part because other cases have set a grossly high standard for what constitutes gravity.

How plausible is a guilty verdict? Bragg’s case faces hurdles including arguments over the statute of limitations, a questionable key witness in the former Trump fixer Michael Cohen, and some fresh legal theories. In short, the Manhattan case seems like perhaps the least significant and most tenuous criminal case. Some Trump critics were dismayed that Bragg was the first to bring criminal charges against the former president.

Department of Justice: Mar-a-Lago Documents

Jack Smith, a special counsel in the U.S. Justice Department, has charged Trump with 37 felonies in connection with his removal of documents from the White House when he left office. The charges include willful retention of national-security information, obstruction of justice, withholding of documents, and false statements. Trump took boxes of documents to properties where they were stored haphazardly, but the indictment centers on his refusal to give them back to the government despite repeated requests.

David A. Graham: This indictment is different

When? Smith filed charges in June 2023. Judge Aileen Cannon has set a trial date of May 20, 2024. In November, she rejected Trump’s request to push that back but said she would reconsider timing in March . Smith faces a de facto deadline of January 20, 2025, at which point Trump or any Republican president would likely shut down a case.

How grave is the allegation? These are, I have written, the stupidest crimes imaginable , but they are nevertheless very serious. Protecting the nation’s secrets is one of the greatest responsibilities of any public official with classified clearance, and not only did Trump put these documents at risk, but he also (allegedly) refused to comply with a subpoena, tried to hide them, and lied to the government through his attorneys.

How plausible is a guilty verdict? This may be the most open-and-shut case, and the facts and legal theory here are pretty straightforward. But Smith seems to have drawn a short straw when he was randomly assigned Cannon, a Trump appointee who has sometimes ruled favorably for Trump on procedural matters. Some legal commentators have even accused her of “ sabotaging ” the case.

Fulton County: Election Subversion

In Fulton County, Georgia, which includes most of Atlanta, District Attorney Fani Willis brought a huge racketeering case against Trump and 18 others, alleging a conspiracy that spread across weeks and states with the aim of stealing the 2020 election.

When? Willis obtained the indictment in August 2023. The number of people charged makes the case unwieldy and difficult to track. Several of them, including Kenneth Chesebro , Sidney Powell , and Jenna Ellis, struck plea deals in the fall. Willis has proposed a trial date of August 5, 2024, for the remaining defendants.

How grave is the allegation? More than any other case, this one attempts to reckon with the full breadth of the assault on democracy following the 2020 election.

How plausible is a guilty verdict? Expert views differ. This is a huge case for a local prosecutor, even in a county as large as Fulton, to bring. The racketeering law allows Willis to sweep in a great deal of material, and she has some strong evidence—such as a call in which Trump asked Georgia Secretary of State Brad Raffensperger to “find” some 11,000 votes. Three major plea deals from co-defendants may also ease Willis’s path, but getting a jury to convict Trump will still be a challenge. Complicating matters, Willis is now under fire for a romantic relationship with an attorney she hired as a special prosecutor.

Department of Justice: Election Subversion

Special Counsel Smith has also charged Trump with four federal felonies in connection with his attempt to remain in power after losing the 2020 election. This case is in court in Washington, D.C.

When? A grand jury indicted Trump on August 1, 2023. The trial was originally schedule for March 4, but Judge Tanya Chutkan said in early February that the date would change, as an appeals court deliberated on Trump’s claim of absolute immunity. A three-judge panel roundly rejected that claim on February 6, but no new trial date has been announced yet. As with the other DOJ case, Smith will need to move quickly, before Trump or any other Republican president could shut down a case upon taking office in January 2025. Other tangential legal skirmishes continue: In October, after verbal attacks by Trump on witnesses and Smith’s wife, Chutkan issued an order limiting what Trump can say about the case.

David A. Graham: Trump attempted a brazen, dead-serious attack on American democracy

How grave is the allegation? This case rivals the Fulton County one in importance. It is narrower, focusing just on Trump and a few key elements of the paperwork coup , but the symbolic weight of the U.S. Justice Department prosecuting an attempt to subvert the American election system is heavy.

How plausible is a guilty verdict? It’s very hard to say. Smith avoided some of the more unconventional potential charges, including aiding insurrection, and everyone watched much of the alleged crime unfold in public in real time, but no precedent exists for a case like this, with a defendant like this.

Additionally …

In more than 30 states , cases have been filed over whether Trump should be thrown off the 2024 ballot under a novel legal theory about the Fourteenth Amendment. Proponents, including J. Michael Luttig and Laurence H. Tribe in The Atlantic , argued that the former president is ineligible to serve again under a clause that disqualifies anyone who took an oath defending the Constitution and then subsequently participated in a rebellion or an insurrection. They said that Trump’s attempt to steal the 2020 election and his incitement of the January 6 riot meet the criteria.

Cases were brought in many states, and state authorities issued conflicting opinions. Several states ruled against removing Trump from the ballot, but the Colorado Supreme Court and the Maine secretary of state both disqualified him, ruling that he had engaged in an insurrection—a remarkable legal finding. Trump then appealed to the U.S. Supreme Court.

When? The U.S. Supreme Court heard arguments in the case on February 8. The timing for a decision is not clear.

How grave is the allegation? In a sense, the claim made here is even graver than the criminal election-subversion cases filed against Trump by the U.S. Department of Justice and in Fulton County, Georgia, because neither of those cases alleges insurrection or rebellion. But the stakes are also much different—rather than criminal conviction, they concern the ability to serve as president.

How plausible is a disqualification? Though there is a robust debate among legal scholars on this question, the nine who matter are the ones on the Supreme Court, and they appeared very skeptical of arguments in favor of disqualification during the February 8 hearing.

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Major law firm looking for more victims in the vince mcmahon scandal, chicago-based firm is seeking more potential victims to come forward following sex trafficking scandal.

Scott Johnson , Reporter/weekend anchor

JACKSONVILLE, Fla. – Embattled former WWE owner Vince McMahon could be facing more legal jeopardy.

The Going Ringside Podcast has detailed the bombshell allegations leveled against McMahon a few weeks ago by a former employee. That employee, Janel Grant, has sued both McMahon and WWE for sex trafficking while she was an employee. Both McMahon and WWE have denied wrongdoing.

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Now, a major Chicago-based law firm has put out an ad for more potential accusers to come forward.

The law firm, Pintas & Mullins Injury Lawyers, put out an ad titled: “Vince McMahon and WWE/UFC Sex Abuse and Exploitation Claims”.

“According to a recent lawsuit, the founder and other leaders forced employees to participate in sexual acts by threatening to terminate their employment and share intimate images of them,” the firm wrote.

McMahon resigned from his position overseeing the company he built the day after the lawsuit was filed. There have also been reports the Federal Government has investigated McMahon and served him with both a search warrant and seized his cell phone. To this point, it’s unclear if that investigation is related to the Grant lawsuit.

The feds have not filed any charges against McMahon.

This comes several months after WWE merged with UFC to create a new company called TKO. McMahon, prior to his resignation, retained 49% of the company while UFC CEO Ari Emanuel controlled 51% of the company.

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Scott is a multi-Emmy Award Winning Anchor and Reporter, who also hosts the “Going Ringside With The Local Station” Podcast. Scott has been a journalist for 25 years, covering stories including six presidential elections, multiple space shuttle launches and dozens of high-profile murder trials.

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    Introduction A case study is one of the most extensively used strategies of qualitative social research. Over the years, its application has expanded by leaps and bounds, and is now being employed in several disciplines of social science such as sociology, management, anthropology, psychology and others.

  2. Top Challenges for Case Study Programs

    Lack of testing environments. Instructors need spaces to test new teaching styles outside of the classroom. Workshops where instructors test-teach short cases and see peer approaches would increase success, confidence, and ease for new case teachers. The challenge of case teaching.

  3. Writing a Case Study Analysis

    Identify two to five key problems. Why do they exist? How do they impact the organization? Who is responsible for them? Uncover Possible Solutions/Changes Needed Review course readings, discussions, outside research, your experience. Select the Best Solution Consider strong supporting evidence, pros, and cons. Is this solution realistic?

  4. Case Study Method: A Step-by-Step Guide for Business Researchers

    Since considerable time and resources are required in conducting researches ( General Accounting Office, 1990 ), any sort of misapprehension regarding the research objective and application of the methodology as well as the validation of the findings may lead to unintended negative consequences ( Baskarada, 2014 ).

  5. What Is a Case Study?

    Propose practical courses of action to resolve a problem Open up new directions for future research TipIf your research is more practical in nature and aims to simultaneously investigate an issue as you solve it, consider conducting action research instead.

  6. Do Your Students Know How to Analyze a Case—Really?

    Step 1: Problem definition. What is the major challenge, problem, opportunity, or decision that has to be made? If there is more than one problem, choose the most important one. Often when solving the key problem, other issues will surface and be addressed.

  7. What the Case Study Method Really Teaches

    What the Case Study Method Really Teaches. Summary. It's been 100 years since Harvard Business School began using the case study method. Beyond teaching specific subject matter, the case study ...

  8. Case study research for better evaluations of complex interventions

    The health sciences have much to learn from scholarship on case study methodology in the social sciences. However, there are multiple challenges in fully exploiting the potential learning from case study research. First are misconceptions that case study research can only provide exploratory or descriptive evidence.

  9. Case Study: Identifying Potential Problems at the Human/Technical

    Case Study: Identifying Potential Problems at the Human/Technical Interface in Complex Clinical Systems Show all authors. Margaret Caudill-Slosberg, MD, PhD, MPH. ... The case study demonstrates that adoption of technology is not a quick fix to the patient safety issue; proactive and ongoing efforts to address the human factors issues raised by ...

  10. The case study approach

    A case study is a research approach that is used to generate an in-depth, multi-faceted understanding of a complex issue in its real-life context. It is an established research design that is used extensively in a wide variety of disciplines, particularly in the social sciences. A case study can be defined in a variety of ways (Table 5 ), the ...

  11. Case Study

    Defnition: A case study is a research method that involves an in-depth examination and analysis of a particular phenomenon or case, such as an individual, organization, community, event, or situation. It is a qualitative research approach that aims to provide a detailed and comprehensive understanding of the case being studied.

  12. Case study: identifying potential problems at the human/technical

    Case study: identifying potential problems at the human/technical interface in complex clinical systems Am J Med Qual. 2005 Nov-Dec;20(6):353-7.doi: 10.1177/1062860605280196. Authors Margaret Caudill-Slosberg 1 , William B Weeks Affiliation

  13. 5 Benefits of the Case Study Method

    5 Benefits of Learning Through Case Studies. 1. Take New Perspectives. The case method prompts you to consider a scenario from another person's perspective. To work through the situation and come up with a solution, you must consider their circumstances, limitations, risk tolerance, stakeholders, resources, and potential consequences to ...

  14. Writing a Case Analysis Paper

    Multiple case studies can be used in a research study; case analysis involves examining a single scenario. Case study research can use two or more cases to examine a problem, often for the purpose of conducting a comparative investigation intended to discover hidden relationships, document emerging trends, or determine variations among ...

  15. Case Study: Definition, Types, Examples & More

    Identify potential solutions: A case study can also help you identify solutions to potential problems. If you have an issue in your business that you are trying to solve, you may be able to take a look at a case study where someone has dealt with a similar situation in the past. ... If you need help solving a difficult problem, a case study may ...

  16. Potential Problem Analysis

    1. IDENTIFY BROAD ASPECTS of the plan that may be prone to failure. 2. IDENTIFY SPECIFIC PROBLEMS that could occur and record them in the first column of a table. 3. ESTIMATE THE RISK of each problem by assigning it a high, medium, or low rating for both its likelihood and the severity of its consequences. 4.

  17. What is a Case Study? Definition & Examples

    A case study is an in-depth investigation of a single person, group, event, or community. This research method involves intensively analyzing a subject to understand its complexity and context. The richness of a case study comes from its ability to capture detailed, qualitative data that can offer insights into a process or subject matter that ...

  18. Big data in healthcare

    These big data systems have shown potential for making fundamental changes in care delivery and discovery of treatments such as reducing health care costs, reducing number of hospital re-admissions, targeted interventions for reducing emergency department (ED) visits, triage of patients in ED, preventing adverse drug effects, and many more 8.

  19. Top 40 Most Popular Case Studies of 2021

    Orders for Yale SOM case studies increased by almost 50% compared to 2020. The top 40 cases were supervised by 19 different Yale SOM faculty members, several supervising multiple cases. CRDT compiled the Top 40 list by combining data from its case store, Google Analytics, and other measures of interest and adoption.

  20. How to write a case study

    1. Identify your goal. Start by defining exactly who your case study will be designed to help. Case studies are about specific instances where a company works with a customer to achieve a goal. Identify which customers are likely to have these goals, as well as other needs the story should cover to appeal to them.

  21. The Practical Challenges of Case Study Research: Lessons from the field

    We describe the two sites used and the challenges faced and outline the lessons we learned from this experience: that the case study site is an active participant in the research, that the personalities within the case study sites will in turn influence the conduct of the research, and that organisations (and individuals) are political. Keywords

  22. Findings from the case studies

    In this chapter we present the findings from the 22 case studies. We provide a rationale for why NPT was found to be the most comprehensive and predictive programme theory for PPI and present the 16 NPT informed mechanisms that were tested within the case studies. We then summarise the key findings and list the contexts that enabled mechanisms. CMO tables are provided, illustrating salient ...

  23. PDF Problem-Solving Skills: Case Studies

    PROBLEM-SOLVING SKILLS are important in any career. They allow you to deal with a wide variety of situations in your professional life. For example, you may encounter problems such as arranging transportation to work, dealing with difficult coworkers, prioritizing daily tasks, and treating uncommon conditions.

  24. Critical transitions in the Amazon forest system

    An ensemble with the 5 coupled models that include a dynamic vegetation module indicates that 18-27% of the biome may transition from stable forest to bistable and that 2-6% may transition to ...

  25. Largest Covid Vaccine Study Yet Finds Links to Health Conditions

    Sponsored Content. Vaccines that protect against severe illness, death and lingering long Covid symptoms from a coronavirus infection were linked to small increases in neurological, blood, and ...

  26. The Cases Against Trump: A Guide

    February 15, 2024, 1:28 PM ET. Not long ago, the idea that a former president—or major-party presidential nominee—would face serious legal jeopardy was nearly unthinkable. Today, merely ...

  27. Major law firm looking for more victims in the Vince McMahon ...

    Major Chicago law firm is seeking more potential victims in the Vince McMahon case. McMahon resigned from his former company WWE a few weeks ago following allegations of sex trafficking by a ...