objective for literature review

Get science-backed answers as you write with Paperpal's Research feature

What is a Literature Review? How to Write It (with Examples)

A literature review is a critical analysis and synthesis of existing research on a particular topic. It provides an overview of the current state of knowledge, identifies gaps, and highlights key findings in the literature. 1 The purpose of a literature review is to situate your own research within the context of existing scholarship, demonstrating your understanding of the topic and showing how your work contributes to the ongoing conversation in the field. Learning how to write a literature review is a critical tool for successful research. Your ability to summarize and synthesize prior research pertaining to a certain topic demonstrates your grasp on the topic of study, and assists in the learning process. 

Table of Contents

• What is the purpose of literature review? 
• a. Habitat Loss and Species Extinction: 
• b. Range Shifts and Phenological Changes: 
• c. Ocean Acidification and Coral Reefs: 
• d. Adaptive Strategies and Conservation Efforts: 
• How to write a good literature review 
• Choose a Topic and Define the Research Question: 
• Decide on the Scope of Your Review: 
• Select Databases for Searches: 
• Conduct Searches and Keep Track: 
• Review the Literature: 
• Organize and Write Your Literature Review: 
• Frequently asked questions 

What is a literature review?

A well-conducted literature review demonstrates the researcher’s familiarity with the existing literature, establishes the context for their own research, and contributes to scholarly conversations on the topic. One of the purposes of a literature review is also to help researchers avoid duplicating previous work and ensure that their research is informed by and builds upon the existing body of knowledge.

What is the purpose of literature review?

A literature review serves several important purposes within academic and research contexts. Here are some key objectives and functions of a literature review: 2  

• Contextualizing the Research Problem: The literature review provides a background and context for the research problem under investigation. It helps to situate the study within the existing body of knowledge. 
• Identifying Gaps in Knowledge: By identifying gaps, contradictions, or areas requiring further research, the researcher can shape the research question and justify the significance of the study. This is crucial for ensuring that the new research contributes something novel to the field. 
• Understanding Theoretical and Conceptual Frameworks: Literature reviews help researchers gain an understanding of the theoretical and conceptual frameworks used in previous studies. This aids in the development of a theoretical framework for the current research. 
• Providing Methodological Insights: Another purpose of literature reviews is that it allows researchers to learn about the methodologies employed in previous studies. This can help in choosing appropriate research methods for the current study and avoiding pitfalls that others may have encountered. 
• Establishing Credibility: A well-conducted literature review demonstrates the researcher’s familiarity with existing scholarship, establishing their credibility and expertise in the field. It also helps in building a solid foundation for the new research. 
• Informing Hypotheses or Research Questions: The literature review guides the formulation of hypotheses or research questions by highlighting relevant findings and areas of uncertainty in existing literature. 

Literature review example

Let’s delve deeper with a literature review example: Let’s say your literature review is about the impact of climate change on biodiversity. You might format your literature review into sections such as the effects of climate change on habitat loss and species extinction, phenological changes, and marine biodiversity. Each section would then summarize and analyze relevant studies in those areas, highlighting key findings and identifying gaps in the research. The review would conclude by emphasizing the need for further research on specific aspects of the relationship between climate change and biodiversity. The following literature review template provides a glimpse into the recommended literature review structure and content, demonstrating how research findings are organized around specific themes within a broader topic. 

Literature Review on Climate Change Impacts on Biodiversity:

Climate change is a global phenomenon with far-reaching consequences, including significant impacts on biodiversity. This literature review synthesizes key findings from various studies: 

a. Habitat Loss and Species Extinction:

Climate change-induced alterations in temperature and precipitation patterns contribute to habitat loss, affecting numerous species (Thomas et al., 2004). The review discusses how these changes increase the risk of extinction, particularly for species with specific habitat requirements. 

b. Range Shifts and Phenological Changes:

Observations of range shifts and changes in the timing of biological events (phenology) are documented in response to changing climatic conditions (Parmesan & Yohe, 2003). These shifts affect ecosystems and may lead to mismatches between species and their resources. 

c. Ocean Acidification and Coral Reefs:

The review explores the impact of climate change on marine biodiversity, emphasizing ocean acidification’s threat to coral reefs (Hoegh-Guldberg et al., 2007). Changes in pH levels negatively affect coral calcification, disrupting the delicate balance of marine ecosystems. 

d. Adaptive Strategies and Conservation Efforts:

Recognizing the urgency of the situation, the literature review discusses various adaptive strategies adopted by species and conservation efforts aimed at mitigating the impacts of climate change on biodiversity (Hannah et al., 2007). It emphasizes the importance of interdisciplinary approaches for effective conservation planning. 

How to write a good literature review

Writing a literature review involves summarizing and synthesizing existing research on a particular topic. A good literature review format should include the following elements. 

Introduction: The introduction sets the stage for your literature review, providing context and introducing the main focus of your review. 

• Opening Statement: Begin with a general statement about the broader topic and its significance in the field. 
• Scope and Purpose: Clearly define the scope of your literature review. Explain the specific research question or objective you aim to address. 
• Organizational Framework: Briefly outline the structure of your literature review, indicating how you will categorize and discuss the existing research. 
• Significance of the Study: Highlight why your literature review is important and how it contributes to the understanding of the chosen topic. 
• Thesis Statement: Conclude the introduction with a concise thesis statement that outlines the main argument or perspective you will develop in the body of the literature review. 

Body: The body of the literature review is where you provide a comprehensive analysis of existing literature, grouping studies based on themes, methodologies, or other relevant criteria. 

• Organize by Theme or Concept: Group studies that share common themes, concepts, or methodologies. Discuss each theme or concept in detail, summarizing key findings and identifying gaps or areas of disagreement. 
• Critical Analysis: Evaluate the strengths and weaknesses of each study. Discuss the methodologies used, the quality of evidence, and the overall contribution of each work to the understanding of the topic. 
• Synthesis of Findings: Synthesize the information from different studies to highlight trends, patterns, or areas of consensus in the literature. 
• Identification of Gaps: Discuss any gaps or limitations in the existing research and explain how your review contributes to filling these gaps. 
• Transition between Sections: Provide smooth transitions between different themes or concepts to maintain the flow of your literature review. 

Conclusion: The conclusion of your literature review should summarize the main findings, highlight the contributions of the review, and suggest avenues for future research. 

• Summary of Key Findings: Recap the main findings from the literature and restate how they contribute to your research question or objective. 
• Contributions to the Field: Discuss the overall contribution of your literature review to the existing knowledge in the field. 
• Implications and Applications: Explore the practical implications of the findings and suggest how they might impact future research or practice. 
• Recommendations for Future Research: Identify areas that require further investigation and propose potential directions for future research in the field. 
• Final Thoughts: Conclude with a final reflection on the importance of your literature review and its relevance to the broader academic community. 

Conducting a literature review

Conducting a literature review is an essential step in research that involves reviewing and analyzing existing literature on a specific topic. It’s important to know how to do a literature review effectively, so here are the steps to follow: 1  

Choose a Topic and Define the Research Question:

• Select a topic that is relevant to your field of study. 
• Clearly define your research question or objective. Determine what specific aspect of the topic do you want to explore? 

Decide on the Scope of Your Review:

• Determine the timeframe for your literature review. Are you focusing on recent developments, or do you want a historical overview? 
• Consider the geographical scope. Is your review global, or are you focusing on a specific region? 
• Define the inclusion and exclusion criteria. What types of sources will you include? Are there specific types of studies or publications you will exclude? 

Select Databases for Searches:

• Identify relevant databases for your field. Examples include PubMed, IEEE Xplore, Scopus, Web of Science, and Google Scholar. 
• Consider searching in library catalogs, institutional repositories, and specialized databases related to your topic. 

Conduct Searches and Keep Track:

• Develop a systematic search strategy using keywords, Boolean operators (AND, OR, NOT), and other search techniques. 
• Record and document your search strategy for transparency and replicability. 
• Keep track of the articles, including publication details, abstracts, and links. Use citation management tools like EndNote, Zotero, or Mendeley to organize your references. 

Review the Literature:

• Evaluate the relevance and quality of each source. Consider the methodology, sample size, and results of studies. 
• Organize the literature by themes or key concepts. Identify patterns, trends, and gaps in the existing research. 
• Summarize key findings and arguments from each source. Compare and contrast different perspectives. 
• Identify areas where there is a consensus in the literature and where there are conflicting opinions. 
• Provide critical analysis and synthesis of the literature. What are the strengths and weaknesses of existing research? 

Organize and Write Your Literature Review:

• Literature review outline should be based on themes, chronological order, or methodological approaches. 
• Write a clear and coherent narrative that synthesizes the information gathered. 
• Use proper citations for each source and ensure consistency in your citation style (APA, MLA, Chicago, etc.). 
• Conclude your literature review by summarizing key findings, identifying gaps, and suggesting areas for future research. 

The literature review sample and detailed advice on writing and conducting a review will help you produce a well-structured report. But remember that a literature review is an ongoing process, and it may be necessary to revisit and update it as your research progresses. 

Frequently asked questions

A literature review is a critical and comprehensive analysis of existing literature (published and unpublished works) on a specific topic or research question and provides a synthesis of the current state of knowledge in a particular field. A well-conducted literature review is crucial for researchers to build upon existing knowledge, avoid duplication of efforts, and contribute to the advancement of their field. It also helps researchers situate their work within a broader context and facilitates the development of a sound theoretical and conceptual framework for their studies.

Literature review is a crucial component of research writing, providing a solid background for a research paper’s investigation. The aim is to keep professionals up to date by providing an understanding of ongoing developments within a specific field, including research methods, and experimental techniques used in that field, and present that knowledge in the form of a written report. Also, the depth and breadth of the literature review emphasizes the credibility of the scholar in his or her field.  

Before writing a literature review, it’s essential to undertake several preparatory steps to ensure that your review is well-researched, organized, and focused. This includes choosing a topic of general interest to you and doing exploratory research on that topic, writing an annotated bibliography, and noting major points, especially those that relate to the position you have taken on the topic. 

Literature reviews and academic research papers are essential components of scholarly work but serve different purposes within the academic realm. 3 A literature review aims to provide a foundation for understanding the current state of research on a particular topic, identify gaps or controversies, and lay the groundwork for future research. Therefore, it draws heavily from existing academic sources, including books, journal articles, and other scholarly publications. In contrast, an academic research paper aims to present new knowledge, contribute to the academic discourse, and advance the understanding of a specific research question. Therefore, it involves a mix of existing literature (in the introduction and literature review sections) and original data or findings obtained through research methods. 

Literature reviews are essential components of academic and research papers, and various strategies can be employed to conduct them effectively. If you want to know how to write a literature review for a research paper, here are four common approaches that are often used by researchers.  Chronological Review: This strategy involves organizing the literature based on the chronological order of publication. It helps to trace the development of a topic over time, showing how ideas, theories, and research have evolved.  Thematic Review: Thematic reviews focus on identifying and analyzing themes or topics that cut across different studies. Instead of organizing the literature chronologically, it is grouped by key themes or concepts, allowing for a comprehensive exploration of various aspects of the topic.  Methodological Review: This strategy involves organizing the literature based on the research methods employed in different studies. It helps to highlight the strengths and weaknesses of various methodologies and allows the reader to evaluate the reliability and validity of the research findings.  Theoretical Review: A theoretical review examines the literature based on the theoretical frameworks used in different studies. This approach helps to identify the key theories that have been applied to the topic and assess their contributions to the understanding of the subject.  It’s important to note that these strategies are not mutually exclusive, and a literature review may combine elements of more than one approach. The choice of strategy depends on the research question, the nature of the literature available, and the goals of the review. Additionally, other strategies, such as integrative reviews or systematic reviews, may be employed depending on the specific requirements of the research.

The literature review format can vary depending on the specific publication guidelines. However, there are some common elements and structures that are often followed. Here is a general guideline for the format of a literature review:  Introduction:   Provide an overview of the topic.  Define the scope and purpose of the literature review.  State the research question or objective.  Body:   Organize the literature by themes, concepts, or chronology.  Critically analyze and evaluate each source.  Discuss the strengths and weaknesses of the studies.  Highlight any methodological limitations or biases.  Identify patterns, connections, or contradictions in the existing research.  Conclusion:   Summarize the key points discussed in the literature review.  Highlight the research gap.  Address the research question or objective stated in the introduction.  Highlight the contributions of the review and suggest directions for future research.

Both annotated bibliographies and literature reviews involve the examination of scholarly sources. While annotated bibliographies focus on individual sources with brief annotations, literature reviews provide a more in-depth, integrated, and comprehensive analysis of existing literature on a specific topic. The key differences are as follows: 

References 

• Denney, A. S., & Tewksbury, R. (2013). How to write a literature review.  Journal of criminal justice education ,  24 (2), 218-234. 
• Pan, M. L. (2016).  Preparing literature reviews: Qualitative and quantitative approaches . Taylor & Francis. 
• Cantero, C. (2019). How to write a literature review.  San José State University Writing Center . 

Paperpal is an AI writing assistant that help academics write better, faster with real-time suggestions for in-depth language and grammar correction. Trained on millions of research manuscripts enhanced by professional academic editors, Paperpal delivers human precision at machine speed.  

Try it for free or upgrade to  Paperpal Prime , which unlocks unlimited access to premium features like academic translation, paraphrasing, contextual synonyms, consistency checks and more. It’s like always having a professional academic editor by your side! Go beyond limitations and experience the future of academic writing.  Get Paperpal Prime now at just US$19 a month!

Related Reads:

• Empirical Research: A Comprehensive Guide for Academics 
• How to Write a Scientific Paper in 10 Steps 
• Life Sciences Papers: 9 Tips for Authors Writing in Biological Sciences
• What is an Argumentative Essay? How to Write It (With Examples)

6 Tips for Post-Doc Researchers to Take Their Career to the Next Level

Self-plagiarism in research: what it is and how to avoid it, you may also like, measuring academic success: definition & strategies for excellence, what is academic writing: tips for students, why traditional editorial process needs an upgrade, paperpal’s new ai research finder empowers authors to..., what is hedging in academic writing  , how to use ai to enhance your college..., ai + human expertise – a paradigm shift..., how to use paperpal to generate emails &..., ai in education: it’s time to change the..., is it ethical to use ai-generated abstracts without....

Want to create or adapt books like this? Learn more about how Pressbooks supports open publishing practices.

The objective of a literature review

Questions to Consider

B. In some fields or contexts, a literature review is referred to as the introduction or the background; why is this true, and does it matter?

The elements of a literature review • The first step in scholarly research is determining the “state of the art” on a topic. This is accomplished by gathering academic research and making sense of it. • The academic literature can be found in scholarly books and journals; the goal is to discover recurring themes, find the latest data, and identify any missing pieces. • The resulting literature review organizes the research in such a way that tells a story about the topic or issue.

The literature review tells a story in which one well-paraphrased summary from a relevant source contributes to and connects with the next in a logical manner, developing and fulfilling the message of the author. It includes analysis of the arguments from the literature, as well as revealing consistent and inconsistent findings. How do varying author insights differ from or conform to previous arguments?

Language in Action

A. How are the terms “critique” and “review” used in everyday life? How are they used in an academic context?

In terms of content, a literature review is intended to:

• Set up a theoretical framework for further research • Show a clear understanding of the key concepts/studies/models related to the topic • Demonstrate knowledge about the history of the research area and any related controversies • Clarify significant definitions and terminology • Develop a space in the existing work for new research

The literature consists of the published works that document a scholarly conversation or progression on a problem or topic in a field of study. Among these are documents that explain the background and show the loose ends in the established research on which a proposed project is based. Although a literature review focuses on primary, peer -reviewed resources, it may begin with background subject information generally found in secondary and tertiary sources such as books and encyclopedias. Following that essential overview, the seminal literature of the field is explored. As a result, while a literature review may consist of research articles tightly focused on a topic with secondary and tertiary sources used more sparingly, all three types of information (primary, secondary, tertiary) are critical.

The literature review, often referred to as the Background or Introduction to a research paper that presents methods, materials, results and discussion, exists in every field and serves many functions in research writing.

Adapted from Frederiksen, L., & Phelps, S. F. (2017). Literature Reviews for Education and Nursing Graduate Students. Open Textbook Library

Review and Reinforce

Two common approaches are simply outlined here. Which seems more common? Which more productive? Why? A. Forward exploration 1. Sources on a topic or problem are gathered. 2. Salient themes are discovered. 3. Research gaps are considered for future research. B. Backward exploration 1. Sources pertaining to an existing research project are gathered. 2. The justification of the research project’s methods or materials are explained and supported based on previously documented research.

Media Attributions

• 2589960988_3eeca91ba4_o © Untitled blue is licensed under a CC BY (Attribution) license

Sourcing, summarizing, and synthesizing:  Skills for effective research writing  Copyright © 2023 by Wendy L. McBride is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License , except where otherwise noted.

Share This Book

Reference management. Clean and simple.

What is a literature review? [with examples]

What is a literature review?

The purpose of a literature review, how to write a literature review, the format of a literature review, general formatting rules, the length of a literature review, literature review examples, frequently asked questions about literature reviews, related articles.

A literature review is an assessment of the sources in a chosen topic of research.

In a literature review, you’re expected to report on the existing scholarly conversation, without adding new contributions.

If you are currently writing one, you've come to the right place. In the following paragraphs, we will explain:

• the objective of a literature review
• how to write a literature review
• the basic format of a literature review

Tip: It’s not always mandatory to add a literature review in a paper. Theses and dissertations often include them, whereas research papers may not. Make sure to consult with your instructor for exact requirements.

The four main objectives of a literature review are:

• Studying the references of your research area
• Summarizing the main arguments
• Identifying current gaps, stances, and issues
• Presenting all of the above in a text

Ultimately, the main goal of a literature review is to provide the researcher with sufficient knowledge about the topic in question so that they can eventually make an intervention.

The format of a literature review is fairly standard. It includes an:

• introduction that briefly introduces the main topic
• body that includes the main discussion of the key arguments
• conclusion that highlights the gaps and issues of the literature

➡️ Take a look at our guide on how to write a literature review to learn more about how to structure a literature review.

First of all, a literature review should have its own labeled section. You should indicate clearly in the table of contents where the literature can be found, and you should label this section as “Literature Review.”

➡️ For more information on writing a thesis, visit our guide on how to structure a thesis .

There is no set amount of words for a literature review, so the length depends on the research. If you are working with a large amount of sources, it will be long. If your paper does not depend entirely on references, it will be short.

Take a look at these three theses featuring great literature reviews:

• School-Based Speech-Language Pathologist's Perceptions of Sensory Food Aversions in Children [ PDF , see page 20]
• Who's Writing What We Read: Authorship in Criminological Research [ PDF , see page 4]
• A Phenomenological Study of the Lived Experience of Online Instructors of Theological Reflection at Christian Institutions Accredited by the Association of Theological Schools [ PDF , see page 56]

Literature reviews are most commonly found in theses and dissertations. However, you find them in research papers as well.

There is no set amount of words for a literature review, so the length depends on the research. If you are working with a large amount of sources, then it will be long. If your paper does not depend entirely on references, then it will be short.

No. A literature review should have its own independent section. You should indicate clearly in the table of contents where the literature review can be found, and label this section as “Literature Review.”

The main goal of a literature review is to provide the researcher with sufficient knowledge about the topic in question so that they can eventually make an intervention.

• Link to facebook
• Link to linkedin
• Link to twitter
• Link to youtube
• Writing Tips

What is the Purpose of a Literature Review?

4-minute read

• 23rd October 2023

If you’re writing a research paper or dissertation , then you’ll most likely need to include a comprehensive literature review . In this post, we’ll review the purpose of literature reviews, why they are so significant, and the specific elements to include in one. Literature reviews can:

1. Provide a foundation for current research.

2. Define key concepts and theories.

3. Demonstrate critical evaluation.

4. Show how research and methodologies have evolved.

5. Identify gaps in existing research.

6. Support your argument.

Keep reading to enter the exciting world of literature reviews!

What is a Literature Review?

A literature review is a critical summary and evaluation of the existing research (e.g., academic journal articles and books) on a specific topic. It is typically included as a separate section or chapter of a research paper or dissertation, serving as a contextual framework for a study. Literature reviews can vary in length depending on the subject and nature of the study, with most being about equal length to other sections or chapters included in the paper. Essentially, the literature review highlights previous studies in the context of your research and summarizes your insights in a structured, organized format. Next, let’s look at the overall purpose of a literature review.

Find this useful?

Subscribe to our newsletter and get writing tips from our editors straight to your inbox.

Literature reviews are considered an integral part of research across most academic subjects and fields. The primary purpose of a literature review in your study is to:

Provide a Foundation for Current Research

Since the literature review provides a comprehensive evaluation of the existing research, it serves as a solid foundation for your current study. It’s a way to contextualize your work and show how your research fits into the broader landscape of your specific area of study.  

Define Key Concepts and Theories

The literature review highlights the central theories and concepts that have arisen from previous research on your chosen topic. It gives your readers a more thorough understanding of the background of your study and why your research is particularly significant .

Demonstrate Critical Evaluation 

A comprehensive literature review shows your ability to critically analyze and evaluate a broad range of source material. And since you’re considering and acknowledging the contribution of key scholars alongside your own, it establishes your own credibility and knowledge.

Show How Research and Methodologies Have Evolved

Another purpose of literature reviews is to provide a historical perspective and demonstrate how research and methodologies have changed over time, especially as data collection methods and technology have advanced. And studying past methodologies allows you, as the researcher, to understand what did and did not work and apply that knowledge to your own research.  

Identify Gaps in Existing Research

Besides discussing current research and methodologies, the literature review should also address areas that are lacking in the existing literature. This helps further demonstrate the relevance of your own research by explaining why your study is necessary to fill the gaps.

Support Your Argument

A good literature review should provide evidence that supports your research questions and hypothesis. For example, your study may show that your research supports existing theories or builds on them in some way. Referencing previous related studies shows your work is grounded in established research and will ultimately be a contribution to the field.  

Literature Review Editing Services 

Ensure your literature review is polished and ready for submission by having it professionally proofread and edited by our expert team. Our literature review editing services will help your research stand out and make an impact. Not convinced yet? Send in your free sample today and see for yourself! 

Share this article:

Post A New Comment

Got content that needs a quick turnaround? Let us polish your work. Explore our editorial business services.

3-minute read

How to Insert a Text Box in a Google Doc

Google Docs is a powerful collaborative tool, and mastering its features can significantly enhance your...

2-minute read

How to Cite the CDC in APA

If you’re writing about health issues, you might need to reference the Centers for Disease...

5-minute read

Six Product Description Generator Tools for Your Product Copy

Introduction If you’re involved with ecommerce, you’re likely familiar with the often painstaking process of...

What Is a Content Editor?

Are you interested in learning more about the role of a content editor and the...

The Benefits of Using an Online Proofreading Service

Proofreading is important to ensure your writing is clear and concise for your readers. Whether...

6 Online AI Presentation Maker Tools

Creating presentations can be time-consuming and frustrating. Trying to construct a visually appealing and informative...

Make sure your writing is the best it can be with our expert English proofreading and editing.

Have a language expert improve your writing

Run a free plagiarism check in 10 minutes, automatically generate references for free.

• Knowledge Base
• Dissertation
• What is a Literature Review? | Guide, Template, & Examples

What is a Literature Review? | Guide, Template, & Examples

Published on 22 February 2022 by Shona McCombes . Revised on 7 June 2022.

What is a literature review? A literature review is a survey of scholarly sources on a specific topic. It provides an overview of current knowledge, allowing you to identify relevant theories, methods, and gaps in the existing research.

There are five key steps to writing a literature review:

• Search for relevant literature
• Evaluate sources
• Identify themes, debates and gaps
• Outline the structure
• Write your literature review

A good literature review doesn’t just summarise sources – it analyses, synthesises, and critically evaluates to give a clear picture of the state of knowledge on the subject.

Instantly correct all language mistakes in your text

Be assured that you'll submit flawless writing. Upload your document to correct all your mistakes.

Table of contents

Why write a literature review, examples of literature reviews, step 1: search for relevant literature, step 2: evaluate and select sources, step 3: identify themes, debates and gaps, step 4: outline your literature review’s structure, step 5: write your literature review, frequently asked questions about literature reviews, introduction.

• Quick Run-through
• Step 1 & 2

When you write a dissertation or thesis, you will have to conduct a literature review to situate your research within existing knowledge. The literature review gives you a chance to:

• Demonstrate your familiarity with the topic and scholarly context
• Develop a theoretical framework and methodology for your research
• Position yourself in relation to other researchers and theorists
• Show how your dissertation addresses a gap or contributes to a debate

You might also have to write a literature review as a stand-alone assignment. In this case, the purpose is to evaluate the current state of research and demonstrate your knowledge of scholarly debates around a topic.

The content will look slightly different in each case, but the process of conducting a literature review follows the same steps. We’ve written a step-by-step guide that you can follow below.

The only proofreading tool specialized in correcting academic writing

The academic proofreading tool has been trained on 1000s of academic texts and by native English editors. Making it the most accurate and reliable proofreading tool for students.

Correct my document today

Writing literature reviews can be quite challenging! A good starting point could be to look at some examples, depending on what kind of literature review you’d like to write.

• Example literature review #1: “Why Do People Migrate? A Review of the Theoretical Literature” ( Theoretical literature review about the development of economic migration theory from the 1950s to today.)
• Example literature review #2: “Literature review as a research methodology: An overview and guidelines” ( Methodological literature review about interdisciplinary knowledge acquisition and production.)
• Example literature review #3: “The Use of Technology in English Language Learning: A Literature Review” ( Thematic literature review about the effects of technology on language acquisition.)
• Example literature review #4: “Learners’ Listening Comprehension Difficulties in English Language Learning: A Literature Review” ( Chronological literature review about how the concept of listening skills has changed over time.)

You can also check out our templates with literature review examples and sample outlines at the links below.

Download Word doc Download Google doc

Before you begin searching for literature, you need a clearly defined topic .

If you are writing the literature review section of a dissertation or research paper, you will search for literature related to your research objectives and questions .

If you are writing a literature review as a stand-alone assignment, you will have to choose a focus and develop a central question to direct your search. Unlike a dissertation research question, this question has to be answerable without collecting original data. You should be able to answer it based only on a review of existing publications.

Make a list of keywords

Start by creating a list of keywords related to your research topic. Include each of the key concepts or variables you’re interested in, and list any synonyms and related terms. You can add to this list if you discover new keywords in the process of your literature search.

• Social media, Facebook, Instagram, Twitter, Snapchat, TikTok
• Body image, self-perception, self-esteem, mental health
• Generation Z, teenagers, adolescents, youth

Search for relevant sources

Use your keywords to begin searching for sources. Some databases to search for journals and articles include:

• Your university’s library catalogue
• Google Scholar
• Project Muse (humanities and social sciences)
• Medline (life sciences and biomedicine)
• EconLit (economics)
• Inspec (physics, engineering and computer science)

You can use boolean operators to help narrow down your search:

Read the abstract to find out whether an article is relevant to your question. When you find a useful book or article, you can check the bibliography to find other relevant sources.

To identify the most important publications on your topic, take note of recurring citations. If the same authors, books or articles keep appearing in your reading, make sure to seek them out.

You probably won’t be able to read absolutely everything that has been written on the topic – you’ll have to evaluate which sources are most relevant to your questions.

For each publication, ask yourself:

• What question or problem is the author addressing?
• What are the key concepts and how are they defined?
• What are the key theories, models and methods? Does the research use established frameworks or take an innovative approach?
• What are the results and conclusions of the study?
• How does the publication relate to other literature in the field? Does it confirm, add to, or challenge established knowledge?
• How does the publication contribute to your understanding of the topic? What are its key insights and arguments?
• What are the strengths and weaknesses of the research?

Make sure the sources you use are credible, and make sure you read any landmark studies and major theories in your field of research.

You can find out how many times an article has been cited on Google Scholar – a high citation count means the article has been influential in the field, and should certainly be included in your literature review.

The scope of your review will depend on your topic and discipline: in the sciences you usually only review recent literature, but in the humanities you might take a long historical perspective (for example, to trace how a concept has changed in meaning over time).

Remember that you can use our template to summarise and evaluate sources you’re thinking about using!

Take notes and cite your sources

As you read, you should also begin the writing process. Take notes that you can later incorporate into the text of your literature review.

It’s important to keep track of your sources with references to avoid plagiarism . It can be helpful to make an annotated bibliography, where you compile full reference information and write a paragraph of summary and analysis for each source. This helps you remember what you read and saves time later in the process.

You can use our free APA Reference Generator for quick, correct, consistent citations.

Prevent plagiarism, run a free check.

To begin organising your literature review’s argument and structure, you need to understand the connections and relationships between the sources you’ve read. Based on your reading and notes, you can look for:

• Trends and patterns (in theory, method or results): do certain approaches become more or less popular over time?
• Themes: what questions or concepts recur across the literature?
• Debates, conflicts and contradictions: where do sources disagree?
• Pivotal publications: are there any influential theories or studies that changed the direction of the field?
• Gaps: what is missing from the literature? Are there weaknesses that need to be addressed?

This step will help you work out the structure of your literature review and (if applicable) show how your own research will contribute to existing knowledge.

• Most research has focused on young women.
• There is an increasing interest in the visual aspects of social media.
• But there is still a lack of robust research on highly-visual platforms like Instagram and Snapchat – this is a gap that you could address in your own research.

There are various approaches to organising the body of a literature review. You should have a rough idea of your strategy before you start writing.

Depending on the length of your literature review, you can combine several of these strategies (for example, your overall structure might be thematic, but each theme is discussed chronologically).

Chronological

The simplest approach is to trace the development of the topic over time. However, if you choose this strategy, be careful to avoid simply listing and summarising sources in order.

Try to analyse patterns, turning points and key debates that have shaped the direction of the field. Give your interpretation of how and why certain developments occurred.

If you have found some recurring central themes, you can organise your literature review into subsections that address different aspects of the topic.

For example, if you are reviewing literature about inequalities in migrant health outcomes, key themes might include healthcare policy, language barriers, cultural attitudes, legal status, and economic access.

Methodological

If you draw your sources from different disciplines or fields that use a variety of research methods , you might want to compare the results and conclusions that emerge from different approaches. For example:

• Look at what results have emerged in qualitative versus quantitative research
• Discuss how the topic has been approached by empirical versus theoretical scholarship
• Divide the literature into sociological, historical, and cultural sources

Theoretical

A literature review is often the foundation for a theoretical framework . You can use it to discuss various theories, models, and definitions of key concepts.

You might argue for the relevance of a specific theoretical approach, or combine various theoretical concepts to create a framework for your research.

Like any other academic text, your literature review should have an introduction , a main body, and a conclusion . What you include in each depends on the objective of your literature review.

The introduction should clearly establish the focus and purpose of the literature review.

If you are writing the literature review as part of your dissertation or thesis, reiterate your central problem or research question and give a brief summary of the scholarly context. You can emphasise the timeliness of the topic (“many recent studies have focused on the problem of x”) or highlight a gap in the literature (“while there has been much research on x, few researchers have taken y into consideration”).

Depending on the length of your literature review, you might want to divide the body into subsections. You can use a subheading for each theme, time period, or methodological approach.

As you write, make sure to follow these tips:

• Summarise and synthesise: give an overview of the main points of each source and combine them into a coherent whole.
• Analyse and interpret: don’t just paraphrase other researchers – add your own interpretations, discussing the significance of findings in relation to the literature as a whole.
• Critically evaluate: mention the strengths and weaknesses of your sources.
• Write in well-structured paragraphs: use transitions and topic sentences to draw connections, comparisons and contrasts.

In the conclusion, you should summarise the key findings you have taken from the literature and emphasise their significance.

If the literature review is part of your dissertation or thesis, reiterate how your research addresses gaps and contributes new knowledge, or discuss how you have drawn on existing theories and methods to build a framework for your research. This can lead directly into your methodology section.

A literature review is a survey of scholarly sources (such as books, journal articles, and theses) related to a specific topic or research question .

It is often written as part of a dissertation , thesis, research paper , or proposal .

There are several reasons to conduct a literature review at the beginning of a research project:

• To familiarise yourself with the current state of knowledge on your topic
• To ensure that you’re not just repeating what others have already done
• To identify gaps in knowledge and unresolved problems that your research can address
• To develop your theoretical framework and methodology
• To provide an overview of the key findings and debates on the topic

Writing the literature review shows your reader how your work relates to existing research and what new insights it will contribute.

The literature review usually comes near the beginning of your  dissertation . After the introduction , it grounds your research in a scholarly field and leads directly to your theoretical framework or methodology .

Cite this Scribbr article

If you want to cite this source, you can copy and paste the citation or click the ‘Cite this Scribbr article’ button to automatically add the citation to our free Reference Generator.

McCombes, S. (2022, June 07). What is a Literature Review? | Guide, Template, & Examples. Scribbr. Retrieved 22 April 2024, from https://www.scribbr.co.uk/thesis-dissertation/literature-review/

Is this article helpful?

Shona McCombes

Other students also liked, how to write a dissertation proposal | a step-by-step guide, what is a theoretical framework | a step-by-step guide, what is a research methodology | steps & tips.

• UConn Library
• Literature Review: The What, Why and How-to Guide
• Introduction

Literature Review: The What, Why and How-to Guide — Introduction

• Getting Started
• How to Pick a Topic
• Strategies to Find Sources
• Evaluating Sources & Lit. Reviews
• Tips for Writing Literature Reviews
• Writing Literature Review: Useful Sites
• Citation Resources
• Other Academic Writings

What are Literature Reviews?

So, what is a literature review? "A literature review is an account of what has been published on a topic by accredited scholars and researchers. In writing the literature review, your purpose is to convey to your reader what knowledge and ideas have been established on a topic, and what their strengths and weaknesses are. As a piece of writing, the literature review must be defined by a guiding concept (e.g., your research objective, the problem or issue you are discussing, or your argumentative thesis). It is not just a descriptive list of the material available, or a set of summaries." Taylor, D.  The literature review: A few tips on conducting it . University of Toronto Health Sciences Writing Centre.

Goals of Literature Reviews

What are the goals of creating a Literature Review?  A literature could be written to accomplish different aims:

• To develop a theory or evaluate an existing theory
• To summarize the historical or existing state of a research topic
• Identify a problem in a field of research 

Baumeister, R. F., & Leary, M. R. (1997). Writing narrative literature reviews .  Review of General Psychology , 1 (3), 311-320.

What kinds of sources require a Literature Review?

• A research paper assigned in a course
• A thesis or dissertation
• A grant proposal
• An article intended for publication in a journal

All these instances require you to collect what has been written about your research topic so that you can demonstrate how your own research sheds new light on the topic.

Types of Literature Reviews

What kinds of literature reviews are written?

Narrative review: The purpose of this type of review is to describe the current state of the research on a specific topic/research and to offer a critical analysis of the literature reviewed. Studies are grouped by research/theoretical categories, and themes and trends, strengths and weakness, and gaps are identified. The review ends with a conclusion section which summarizes the findings regarding the state of the research of the specific study, the gaps identify and if applicable, explains how the author's research will address gaps identify in the review and expand the knowledge on the topic reviewed.

• Example : Predictors and Outcomes of U.S. Quality Maternity Leave: A Review and Conceptual Framework:  10.1177/08948453211037398  

Systematic review : "The authors of a systematic review use a specific procedure to search the research literature, select the studies to include in their review, and critically evaluate the studies they find." (p. 139). Nelson, L. K. (2013). Research in Communication Sciences and Disorders . Plural Publishing.

• Example : The effect of leave policies on increasing fertility: a systematic review:  10.1057/s41599-022-01270-w

Meta-analysis : "Meta-analysis is a method of reviewing research findings in a quantitative fashion by transforming the data from individual studies into what is called an effect size and then pooling and analyzing this information. The basic goal in meta-analysis is to explain why different outcomes have occurred in different studies." (p. 197). Roberts, M. C., & Ilardi, S. S. (2003). Handbook of Research Methods in Clinical Psychology . Blackwell Publishing.

• Example : Employment Instability and Fertility in Europe: A Meta-Analysis:  10.1215/00703370-9164737

Meta-synthesis : "Qualitative meta-synthesis is a type of qualitative study that uses as data the findings from other qualitative studies linked by the same or related topic." (p.312). Zimmer, L. (2006). Qualitative meta-synthesis: A question of dialoguing with texts .  Journal of Advanced Nursing , 53 (3), 311-318.

• Example : Women’s perspectives on career successes and barriers: A qualitative meta-synthesis:  10.1177/05390184221113735

Literature Reviews in the Health Sciences

• UConn Health subject guide on systematic reviews Explanation of the different review types used in health sciences literature as well as tools to help you find the right review type
• << Previous: Getting Started
• Next: How to Pick a Topic >>
• Last Updated: Sep 21, 2022 2:16 PM
• URL: https://guides.lib.uconn.edu/literaturereview

• University of Texas Libraries

Literature Reviews

• What is a literature review?
• Steps in the Literature Review Process
• Define your research question
• Determine inclusion and exclusion criteria
• Choose databases and search
• Review Results
• Synthesize Results
• Analyze Results
• Librarian Support

What is a Literature Review?

A literature or narrative review is a comprehensive review and analysis of the published literature on a specific topic or research question. The literature that is reviewed contains: books, articles, academic articles, conference proceedings, association papers, and dissertations. It contains the most pertinent studies and points to important past and current research and practices. It provides background and context, and shows how your research will contribute to the field. 

A literature review should: 

• Provide a comprehensive and updated review of the literature;
• Explain why this review has taken place;
• Articulate a position or hypothesis;
• Acknowledge and account for conflicting and corroborating points of view

From  S age Research Methods

Purpose of a Literature Review

A literature review can be written as an introduction to a study to:

• Demonstrate how a study fills a gap in research
• Compare a study with other research that's been done

Or it can be a separate work (a research article on its own) which:

• Organizes or describes a topic
• Describes variables within a particular issue/problem

Limitations of a Literature Review

Some of the limitations of a literature review are:

• It's a snapshot in time. Unlike other reviews, this one has beginning, a middle and an end. There may be future developments that could make your work less relevant.
• It may be too focused. Some niche studies may miss the bigger picture.
• It can be difficult to be comprehensive. There is no way to make sure all the literature on a topic was considered.
• It is easy to be biased if you stick to top tier journals. There may be other places where people are publishing exemplary research. Look to open access publications and conferences to reflect a more inclusive collection. Also, make sure to include opposing views (and not just supporting evidence).

Source: Grant, Maria J., and Andrew Booth. “A Typology of Reviews: An Analysis of 14 Review Types and Associated Methodologies.” Health Information & Libraries Journal, vol. 26, no. 2, June 2009, pp. 91–108. Wiley Online Library, doi:10.1111/j.1471-1842.2009.00848.x.

Meryl Brodsky : Communication and Information Studies

Hannah Chapman Tripp : Biology, Neuroscience

Carolyn Cunningham : Human Development & Family Sciences, Psychology, Sociology

Larayne Dallas : Engineering

Janelle Hedstrom : Special Education, Curriculum & Instruction, Ed Leadership & Policy ​

Susan Macicak : Linguistics

Imelda Vetter : Dell Medical School

For help in other subject areas, please see the guide to library specialists by subject .

Periodically, UT Libraries runs a workshop covering the basics and library support for literature reviews. While we try to offer these once per academic year, we find providing the recording to be helpful to community members who have missed the session. Following is the most recent recording of the workshop, Conducting a Literature Review. To view the recording, a UT login is required.

• October 26, 2022 recording
• Last Updated: Oct 26, 2022 2:49 PM
• URL: https://guides.lib.utexas.edu/literaturereviews

• Library Homepage

Literature Review: The What, Why and How-to Guide: Literature Reviews?

• Literature Reviews?
• Strategies to Finding Sources
• Keeping up with Research!
• Evaluating Sources & Literature Reviews
• Organizing for Writing
• Writing Literature Review
• Other Academic Writings

What is a Literature Review?

So, what is a literature review .

"A literature review is an account of what has been published on a topic by accredited scholars and researchers. In writing the literature review, your purpose is to convey to your reader what knowledge and ideas have been established on a topic, and what their strengths and weaknesses are. As a piece of writing, the literature review must be defined by a guiding concept (e.g., your research objective, the problem or issue you are discussing, or your argumentative thesis). It is not just a descriptive list of the material available or a set of summaries." - Quote from Taylor, D. (n.d)."The Literature Review: A Few Tips on Conducting it".

• Citation: "The Literature Review: A Few Tips on Conducting it"

What kinds of literature reviews are written?

Each field has a particular way to do reviews for academic research literature. In the social sciences and humanities the most common are:

• Narrative Reviews: The purpose of this type of review is to describe the current state of the research on a specific research topic and to offer a critical analysis of the literature reviewed. Studies are grouped by research/theoretical categories, and themes and trends, strengths and weaknesses, and gaps are identified. The review ends with a conclusion section that summarizes the findings regarding the state of the research of the specific study, the gaps identify and if applicable, explains how the author's research will address gaps identify in the review and expand the knowledge on the topic reviewed.
• Book review essays/ Historiographical review essays : A type of literature review typical in History and related fields, e.g., Latin American studies. For example, the Latin American Research Review explains that the purpose of this type of review is to “(1) to familiarize readers with the subject, approach, arguments, and conclusions found in a group of books whose common focus is a historical period; a country or region within Latin America; or a practice, development, or issue of interest to specialists and others; (2) to locate these books within current scholarship, critical methodologies, and approaches; and (3) to probe the relation of these new books to previous work on the subject, especially canonical texts. Unlike individual book reviews, the cluster reviews found in LARR seek to address the state of the field or discipline and not solely the works at issue.” - LARR

What are the Goals of Creating a Literature Review?

• To develop a theory or evaluate an existing theory
• To summarize the historical or existing state of a research topic
• Identify a problem in a field of research 
• Baumeister, R.F. & Leary, M.R. (1997). "Writing narrative literature reviews," Review of General Psychology , 1(3), 311-320.

When do you need to write a Literature Review?

• When writing a prospectus or a thesis/dissertation
• When writing a research paper
• When writing a grant proposal

In all these cases you need to dedicate a chapter in these works to showcase what has been written about your research topic and to point out how your own research will shed new light into a body of scholarship.

Where I can find examples of Literature Reviews?

Note:  In the humanities, even if they don't use the term "literature review", they may have a dedicated  chapter that reviewed the "critical bibliography" or they incorporated that review in the introduction or first chapter of the dissertation, book, or article.

• UCSB electronic theses and dissertations In partnership with the Graduate Division, the UC Santa Barbara Library is making available theses and dissertations produced by UCSB students. Currently included in ADRL are theses and dissertations that were originally filed electronically, starting in 2011. In future phases of ADRL, all theses and dissertations created by UCSB students may be digitized and made available.

Where to Find Standalone Literature Reviews

Literature reviews are also written as standalone articles as a way to survey a particular research topic in-depth. This type of literature review looks at a topic from a historical perspective to see how the understanding of the topic has changed over time. 

• Find e-Journals for Standalone Literature Reviews The best way to get familiar with and to learn how to write literature reviews is by reading them. You can use our Journal Search option to find journals that specialize in publishing literature reviews from major disciplines like anthropology, sociology, etc. Usually these titles are called, "Annual Review of [discipline name] OR [Discipline name] Review. This option works best if you know the title of the publication you are looking for. Below are some examples of these journals! more... less... Journal Search can be found by hovering over the link for Research on the library website.

Social Sciences

• Annual Review of Anthropology
• Annual Review of Political Science
• Annual Review of Sociology
• Ethnic Studies Review

Hard science and health sciences:

• Annual Review of Biomedical Data Science
• Annual Review of Materials Science
• Systematic Review From journal site: "The journal Systematic Reviews encompasses all aspects of the design, conduct, and reporting of systematic reviews" in the health sciences.
• << Previous: Overview
• Next: Strategies to Finding Sources >>
• Last Updated: Mar 5, 2024 11:44 AM
• URL: https://guides.library.ucsb.edu/litreview

Research Methods

• Getting Started
• Literature Review Research
• Research Design
• Research Design By Discipline
• SAGE Research Methods
• Teaching with SAGE Research Methods

Literature Review

• What is a Literature Review?
• What is NOT a Literature Review?
• Purposes of a Literature Review
• Types of Literature Reviews
• Literature Reviews vs. Systematic Reviews
• Systematic vs. Meta-Analysis

Literature Review  is a comprehensive survey of the works published in a particular field of study or line of research, usually over a specific period of time, in the form of an in-depth, critical bibliographic essay or annotated list in which attention is drawn to the most significant works.

Also, we can define a literature review as the collected body of scholarly works related to a topic:

• Summarizes and analyzes previous research relevant to a topic
• Includes scholarly books and articles published in academic journals
• Can be an specific scholarly paper or a section in a research paper

The objective of a Literature Review is to find previous published scholarly works relevant to an specific topic

• Help gather ideas or information
• Keep up to date in current trends and findings
• Help develop new questions

A literature review is important because it:

• Explains the background of research on a topic.
• Demonstrates why a topic is significant to a subject area.
• Helps focus your own research questions or problems
• Discovers relationships between research studies/ideas.
• Suggests unexplored ideas or populations
• Identifies major themes, concepts, and researchers on a topic.
• Tests assumptions; may help counter preconceived ideas and remove unconscious bias.
• Identifies critical gaps, points of disagreement, or potentially flawed methodology or theoretical approaches.
• Indicates potential directions for future research.

All content in this section is from Literature Review Research from Old Dominion University 

Keep in mind the following, a literature review is NOT:

Not an essay 

Not an annotated bibliography  in which you summarize each article that you have reviewed.  A literature review goes beyond basic summarizing to focus on the critical analysis of the reviewed works and their relationship to your research question.

Not a research paper   where you select resources to support one side of an issue versus another.  A lit review should explain and consider all sides of an argument in order to avoid bias, and areas of agreement and disagreement should be highlighted.

A literature review serves several purposes. For example, it

• provides thorough knowledge of previous studies; introduces seminal works.
• helps focus one’s own research topic.
• identifies a conceptual framework for one’s own research questions or problems; indicates potential directions for future research.
• suggests previously unused or underused methodologies, designs, quantitative and qualitative strategies.
• identifies gaps in previous studies; identifies flawed methodologies and/or theoretical approaches; avoids replication of mistakes.
• helps the researcher avoid repetition of earlier research.
• suggests unexplored populations.
• determines whether past studies agree or disagree; identifies controversy in the literature.
• tests assumptions; may help counter preconceived ideas and remove unconscious bias.

As Kennedy (2007) notes*, it is important to think of knowledge in a given field as consisting of three layers. First, there are the primary studies that researchers conduct and publish. Second are the reviews of those studies that summarize and offer new interpretations built from and often extending beyond the original studies. Third, there are the perceptions, conclusions, opinion, and interpretations that are shared informally that become part of the lore of field. In composing a literature review, it is important to note that it is often this third layer of knowledge that is cited as "true" even though it often has only a loose relationship to the primary studies and secondary literature reviews.

Given this, while literature reviews are designed to provide an overview and synthesis of pertinent sources you have explored, there are several approaches to how they can be done, depending upon the type of analysis underpinning your study. Listed below are definitions of types of literature reviews:

Argumentative Review      This form examines literature selectively in order to support or refute an argument, deeply imbedded assumption, or philosophical problem already established in the literature. The purpose is to develop a body of literature that establishes a contrarian viewpoint. Given the value-laden nature of some social science research [e.g., educational reform; immigration control], argumentative approaches to analyzing the literature can be a legitimate and important form of discourse. However, note that they can also introduce problems of bias when they are used to to make summary claims of the sort found in systematic reviews.

Integrative Review      Considered a form of research that reviews, critiques, and synthesizes representative literature on a topic in an integrated way such that new frameworks and perspectives on the topic are generated. The body of literature includes all studies that address related or identical hypotheses. A well-done integrative review meets the same standards as primary research in regard to clarity, rigor, and replication.

Historical Review      Few things rest in isolation from historical precedent. Historical reviews are focused on examining research throughout a period of time, often starting with the first time an issue, concept, theory, phenomena emerged in the literature, then tracing its evolution within the scholarship of a discipline. The purpose is to place research in a historical context to show familiarity with state-of-the-art developments and to identify the likely directions for future research.

Methodological Review      A review does not always focus on what someone said [content], but how they said it [method of analysis]. This approach provides a framework of understanding at different levels (i.e. those of theory, substantive fields, research approaches and data collection and analysis techniques), enables researchers to draw on a wide variety of knowledge ranging from the conceptual level to practical documents for use in fieldwork in the areas of ontological and epistemological consideration, quantitative and qualitative integration, sampling, interviewing, data collection and data analysis, and helps highlight many ethical issues which we should be aware of and consider as we go through our study.

Systematic Review      This form consists of an overview of existing evidence pertinent to a clearly formulated research question, which uses pre-specified and standardized methods to identify and critically appraise relevant research, and to collect, report, and analyse data from the studies that are included in the review. Typically it focuses on a very specific empirical question, often posed in a cause-and-effect form, such as "To what extent does A contribute to B?"

Theoretical Review      The purpose of this form is to concretely examine the corpus of theory that has accumulated in regard to an issue, concept, theory, phenomena. The theoretical literature review help establish what theories already exist, the relationships between them, to what degree the existing theories have been investigated, and to develop new hypotheses to be tested. Often this form is used to help establish a lack of appropriate theories or reveal that current theories are inadequate for explaining new or emerging research problems. The unit of analysis can focus on a theoretical concept or a whole theory or framework.

* Kennedy, Mary M. "Defining a Literature."  Educational Researcher  36 (April 2007): 139-147.

All content in this section is from The Literature Review created by Dr. Robert Larabee USC

Robinson, P. and Lowe, J. (2015),  Literature reviews vs systematic reviews.  Australian and New Zealand Journal of Public Health, 39: 103-103. doi: 10.1111/1753-6405.12393

What's in the name? The difference between a Systematic Review and a Literature Review, and why it matters . By Lynn Kysh from University of Southern California

Systematic review or meta-analysis?

A  systematic review  answers a defined research question by collecting and summarizing all empirical evidence that fits pre-specified eligibility criteria.

A  meta-analysis  is the use of statistical methods to summarize the results of these studies.

Systematic reviews, just like other research articles, can be of varying quality. They are a significant piece of work (the Centre for Reviews and Dissemination at York estimates that a team will take 9-24 months), and to be useful to other researchers and practitioners they should have:

• clearly stated objectives with pre-defined eligibility criteria for studies
• explicit, reproducible methodology
• a systematic search that attempts to identify all studies
• assessment of the validity of the findings of the included studies (e.g. risk of bias)
• systematic presentation, and synthesis, of the characteristics and findings of the included studies

Not all systematic reviews contain meta-analysis. 

Meta-analysis is the use of statistical methods to summarize the results of independent studies. By combining information from all relevant studies, meta-analysis can provide more precise estimates of the effects of health care than those derived from the individual studies included within a review.  More information on meta-analyses can be found in  Cochrane Handbook, Chapter 9 .

A meta-analysis goes beyond critique and integration and conducts secondary statistical analysis on the outcomes of similar studies.  It is a systematic review that uses quantitative methods to synthesize and summarize the results.

An advantage of a meta-analysis is the ability to be completely objective in evaluating research findings.  Not all topics, however, have sufficient research evidence to allow a meta-analysis to be conducted.  In that case, an integrative review is an appropriate strategy. 

Some of the content in this section is from Systematic reviews and meta-analyses: step by step guide created by Kate McAllister.

• << Previous: Getting Started
• Next: Research Design >>
• Last Updated: Aug 21, 2023 4:07 PM
• URL: https://guides.lib.udel.edu/researchmethods

How To Structure Your Literature Review

3 options to help structure your chapter.

By: Amy Rommelspacher (PhD) | Reviewer: Dr Eunice Rautenbach | November 2020 (Updated May 2023)

Writing the literature review chapter can seem pretty daunting when you’re piecing together your dissertation or thesis. As  we’ve discussed before , a good literature review needs to achieve a few very important objectives – it should:

• Demonstrate your knowledge of the research topic
• Identify the gaps in the literature and show how your research links to these
• Provide the foundation for your conceptual framework (if you have one)
• Inform your own  methodology and research design

To achieve this, your literature review needs a well-thought-out structure . Get the structure of your literature review chapter wrong and you’ll struggle to achieve these objectives. Don’t worry though – in this post, we’ll look at how to structure your literature review for maximum impact (and marks!).

But wait – is this the right time?

Deciding on the structure of your literature review should come towards the end of the literature review process – after you have collected and digested the literature, but before you start writing the chapter. 

In other words, you need to first develop a rich understanding of the literature before you even attempt to map out a structure. There’s no use trying to develop a structure before you’ve fully wrapped your head around the existing research.

Equally importantly, you need to have a structure in place before you start writing , or your literature review will most likely end up a rambling, disjointed mess. 

Importantly, don’t feel that once you’ve defined a structure you can’t iterate on it. It’s perfectly natural to adjust as you engage in the writing process. As we’ve discussed before , writing is a way of developing your thinking, so it’s quite common for your thinking to change – and therefore, for your chapter structure to change – as you write. 

Need a helping hand?

Like any other chapter in your thesis or dissertation, your literature review needs to have a clear, logical structure. At a minimum, it should have three essential components – an  introduction , a  body   and a  conclusion . 

Let’s take a closer look at each of these.

1: The Introduction Section

Just like any good introduction, the introduction section of your literature review should introduce the purpose and layout (organisation) of the chapter. In other words, your introduction needs to give the reader a taste of what’s to come, and how you’re going to lay that out. Essentially, you should provide the reader with a high-level roadmap of your chapter to give them a taste of the journey that lies ahead.

Here’s an example of the layout visualised in a literature review introduction:

Your introduction should also outline your topic (including any tricky terminology or jargon) and provide an explanation of the scope of your literature review – in other words, what you  will   and  won’t   be covering (the delimitations ). This helps ringfence your review and achieve a clear focus . The clearer and narrower your focus, the deeper you can dive into the topic (which is typically where the magic lies). 

Depending on the nature of your project, you could also present your stance or point of view at this stage. In other words, after grappling with the literature you’ll have an opinion about what the trends and concerns are in the field as well as what’s lacking. The introduction section can then present these ideas so that it is clear to examiners that you’re aware of how your research connects with existing knowledge .

2: The Body Section

The body of your literature review is the centre of your work. This is where you’ll present, analyse, evaluate and synthesise the existing research. In other words, this is where you’re going to earn (or lose) the most marks. Therefore, it’s important to carefully think about how you will organise your discussion to present it in a clear way. 

The body of your literature review should do just as the description of this chapter suggests. It should “review” the literature – in other words, identify, analyse, and synthesise it. So, when thinking about structuring your literature review, you need to think about which structural approach will provide the best “review” for your specific type of research and objectives (we’ll get to this shortly).

There are (broadly speaking)  three options  for organising your literature review.

Option 1: Chronological (according to date)

Organising the literature chronologically is one of the simplest ways to structure your literature review. You start with what was published first and work your way through the literature until you reach the work published most recently. Pretty straightforward.

The benefit of this option is that it makes it easy to discuss the developments and debates in the field as they emerged over time. Organising your literature chronologically also allows you to highlight how specific articles or pieces of work might have changed the course of the field – in other words, which research has had the most impact . Therefore, this approach is very useful when your research is aimed at understanding how the topic has unfolded over time and is often used by scholars in the field of history. That said, this approach can be utilised by anyone that wants to explore change over time .

For example , if a student of politics is investigating how the understanding of democracy has evolved over time, they could use the chronological approach to provide a narrative that demonstrates how this understanding has changed through the ages.

Here are some questions you can ask yourself to help you structure your literature review chronologically.

• What is the earliest literature published relating to this topic?
• How has the field changed over time? Why?
• What are the most recent discoveries/theories?

In some ways, chronology plays a part whichever way you decide to structure your literature review, because you will always, to a certain extent, be analysing how the literature has developed. However, with the chronological approach, the emphasis is very firmly on how the discussion has evolved over time , as opposed to how all the literature links together (which we’ll discuss next ).

Option 2: Thematic (grouped by theme)

The thematic approach to structuring a literature review means organising your literature by theme or category – for example, by independent variables (i.e. factors that have an impact on a specific outcome).

As you’ve been collecting and synthesising literature , you’ll likely have started seeing some themes or patterns emerging. You can then use these themes or patterns as a structure for your body discussion. The thematic approach is the most common approach and is useful for structuring literature reviews in most fields.

For example, if you were researching which factors contributed towards people trusting an organisation, you might find themes such as consumers’ perceptions of an organisation’s competence, benevolence and integrity. Structuring your literature review thematically would mean structuring your literature review’s body section to discuss each of these themes, one section at a time.

Here are some questions to ask yourself when structuring your literature review by themes:

• Are there any patterns that have come to light in the literature?
• What are the central themes and categories used by the researchers?
• Do I have enough evidence of these themes?

PS – you can see an example of a thematically structured literature review in our literature review sample walkthrough video here.

Option 3: Methodological

The methodological option is a way of structuring your literature review by the research methodologies used . In other words, organising your discussion based on the angle from which each piece of research was approached – for example, qualitative , quantitative or mixed  methodologies.

Structuring your literature review by methodology can be useful if you are drawing research from a variety of disciplines and are critiquing different methodologies. The point of this approach is to question  how  existing research has been conducted, as opposed to  what  the conclusions and/or findings the research were.

For example, a sociologist might centre their research around critiquing specific fieldwork practices. Their literature review will then be a summary of the fieldwork methodologies used by different studies.

Here are some questions you can ask yourself when structuring your literature review according to methodology:

• Which methodologies have been utilised in this field?
• Which methodology is the most popular (and why)?
• What are the strengths and weaknesses of the various methodologies?
• How can the existing methodologies inform my own methodology?

3: The Conclusion Section

Once you’ve completed the body section of your literature review using one of the structural approaches we discussed above, you’ll need to “wrap up” your literature review and pull all the pieces together to set the direction for the rest of your dissertation or thesis.

The conclusion is where you’ll present the key findings of your literature review. In this section, you should emphasise the research that is especially important to your research questions and highlight the gaps that exist in the literature. Based on this, you need to make it clear what you will add to the literature – in other words, justify your own research by showing how it will help fill one or more of the gaps you just identified.

Last but not least, if it’s your intention to develop a conceptual framework for your dissertation or thesis, the conclusion section is a good place to present this.

Example: Thematically Structured Review

In the video below, we unpack a literature review chapter so that you can see an example of a thematically structure review in practice.

Let’s Recap

In this article, we’ve  discussed how to structure your literature review for maximum impact. Here’s a quick recap of what  you need to keep in mind when deciding on your literature review structure:

• Just like other chapters, your literature review needs a clear introduction , body and conclusion .
• The introduction section should provide an overview of what you will discuss in your literature review.
• The body section of your literature review can be organised by chronology , theme or methodology . The right structural approach depends on what you’re trying to achieve with your research.
• The conclusion section should draw together the key findings of your literature review and link them to your research questions.

If you’re ready to get started, be sure to download our free literature review template to fast-track your chapter outline.

Psst… there’s more!

This post is an extract from our bestselling short course, Literature Review Bootcamp . If you want to work smart, you don't want to miss this .

You Might Also Like:

27 Comments

Great work. This is exactly what I was looking for and helps a lot together with your previous post on literature review. One last thing is missing: a link to a great literature chapter of an journal article (maybe with comments of the different sections in this review chapter). Do you know any great literature review chapters?

I agree with you Marin… A great piece

I agree with Marin. This would be quite helpful if you annotate a nicely structured literature from previously published research articles.

Awesome article for my research.

I thank you immensely for this wonderful guide

It is indeed thought and supportive work for the futurist researcher and students

Very educative and good time to get guide. Thank you

Great work, very insightful. Thank you.

Thanks for this wonderful presentation. My question is that do I put all the variables into a single conceptual framework or each hypothesis will have it own conceptual framework?

Thank you very much, very helpful

This is very educative and precise . Thank you very much for dropping this kind of write up .

Pheeww, so damn helpful, thank you for this informative piece.

I’m doing a research project topic ; stool analysis for parasitic worm (enteric) worm, how do I structure it, thanks.

comprehensive explanation. Help us by pasting the URL of some good “literature review” for better understanding.

great piece. thanks for the awesome explanation. it is really worth sharing. I have a little question, if anyone can help me out, which of the options in the body of literature can be best fit if you are writing an architectural thesis that deals with design?

I am doing a research on nanofluids how can l structure it?

Beautifully clear.nThank you!

Lucid! Thankyou!

Brilliant work, well understood, many thanks

I like how this was so clear with simple language 😊😊 thank you so much 😊 for these information 😊

Insightful. I was struggling to come up with a sensible literature review but this has been really helpful. Thank you!

You have given thought-provoking information about the review of the literature.

Thank you. It has made my own research better and to impart your work to students I teach

I learnt a lot from this teaching. It’s a great piece.

I am doing research on EFL teacher motivation for his/her job. How Can I structure it? Is there any detailed template, additional to this?

You are so cool! I do not think I’ve read through something like this before. So nice to find somebody with some genuine thoughts on this issue. Seriously.. thank you for starting this up. This site is one thing that is required on the internet, someone with a little originality!

I’m asked to do conceptual, theoretical and empirical literature, and i just don’t know how to structure it

Submit a Comment Cancel reply

Your email address will not be published. Required fields are marked *

Save my name, email, and website in this browser for the next time I comment.

• Print Friendly

An official website of the United States government

The .gov means it's official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings
• Browse Titles

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.

Lau F, Kuziemsky C, editors. Handbook of eHealth Evaluation: An Evidence-based Approach [Internet]. Victoria (BC): University of Victoria; 2017 Feb 27.

Handbook of eHealth Evaluation: An Evidence-based Approach [Internet].

Chapter 9 methods for literature reviews.

Guy Paré and Spyros Kitsiou .

9.1. Introduction

Literature reviews play a critical role in scholarship because science remains, first and foremost, a cumulative endeavour ( vom Brocke et al., 2009 ). As in any academic discipline, rigorous knowledge syntheses are becoming indispensable in keeping up with an exponentially growing eHealth literature, assisting practitioners, academics, and graduate students in finding, evaluating, and synthesizing the contents of many empirical and conceptual papers. Among other methods, literature reviews are essential for: (a) identifying what has been written on a subject or topic; (b) determining the extent to which a specific research area reveals any interpretable trends or patterns; (c) aggregating empirical findings related to a narrow research question to support evidence-based practice; (d) generating new frameworks and theories; and (e) identifying topics or questions requiring more investigation ( Paré, Trudel, Jaana, & Kitsiou, 2015 ).

Literature reviews can take two major forms. The most prevalent one is the “literature review” or “background” section within a journal paper or a chapter in a graduate thesis. This section synthesizes the extant literature and usually identifies the gaps in knowledge that the empirical study addresses ( Sylvester, Tate, & Johnstone, 2013 ). It may also provide a theoretical foundation for the proposed study, substantiate the presence of the research problem, justify the research as one that contributes something new to the cumulated knowledge, or validate the methods and approaches for the proposed study ( Hart, 1998 ; Levy & Ellis, 2006 ).

The second form of literature review, which is the focus of this chapter, constitutes an original and valuable work of research in and of itself ( Paré et al., 2015 ). Rather than providing a base for a researcher’s own work, it creates a solid starting point for all members of the community interested in a particular area or topic ( Mulrow, 1987 ). The so-called “review article” is a journal-length paper which has an overarching purpose to synthesize the literature in a field, without collecting or analyzing any primary data ( Green, Johnson, & Adams, 2006 ).

When appropriately conducted, review articles represent powerful information sources for practitioners looking for state-of-the art evidence to guide their decision-making and work practices ( Paré et al., 2015 ). Further, high-quality reviews become frequently cited pieces of work which researchers seek out as a first clear outline of the literature when undertaking empirical studies ( Cooper, 1988 ; Rowe, 2014 ). Scholars who track and gauge the impact of articles have found that review papers are cited and downloaded more often than any other type of published article ( Cronin, Ryan, & Coughlan, 2008 ; Montori, Wilczynski, Morgan, Haynes, & Hedges, 2003 ; Patsopoulos, Analatos, & Ioannidis, 2005 ). The reason for their popularity may be the fact that reading the review enables one to have an overview, if not a detailed knowledge of the area in question, as well as references to the most useful primary sources ( Cronin et al., 2008 ). Although they are not easy to conduct, the commitment to complete a review article provides a tremendous service to one’s academic community ( Paré et al., 2015 ; Petticrew & Roberts, 2006 ). Most, if not all, peer-reviewed journals in the fields of medical informatics publish review articles of some type.

The main objectives of this chapter are fourfold: (a) to provide an overview of the major steps and activities involved in conducting a stand-alone literature review; (b) to describe and contrast the different types of review articles that can contribute to the eHealth knowledge base; (c) to illustrate each review type with one or two examples from the eHealth literature; and (d) to provide a series of recommendations for prospective authors of review articles in this domain.

9.2. Overview of the Literature Review Process and Steps

As explained in Templier and Paré (2015) , there are six generic steps involved in conducting a review article:

• formulating the research question(s) and objective(s),
• searching the extant literature,
• screening for inclusion,
• assessing the quality of primary studies,
• extracting data, and
• analyzing data.

Although these steps are presented here in sequential order, one must keep in mind that the review process can be iterative and that many activities can be initiated during the planning stage and later refined during subsequent phases ( Finfgeld-Connett & Johnson, 2013 ; Kitchenham & Charters, 2007 ).

Formulating the research question(s) and objective(s): As a first step, members of the review team must appropriately justify the need for the review itself ( Petticrew & Roberts, 2006 ), identify the review’s main objective(s) ( Okoli & Schabram, 2010 ), and define the concepts or variables at the heart of their synthesis ( Cooper & Hedges, 2009 ; Webster & Watson, 2002 ). Importantly, they also need to articulate the research question(s) they propose to investigate ( Kitchenham & Charters, 2007 ). In this regard, we concur with Jesson, Matheson, and Lacey (2011) that clearly articulated research questions are key ingredients that guide the entire review methodology; they underscore the type of information that is needed, inform the search for and selection of relevant literature, and guide or orient the subsequent analysis. Searching the extant literature: The next step consists of searching the literature and making decisions about the suitability of material to be considered in the review ( Cooper, 1988 ). There exist three main coverage strategies. First, exhaustive coverage means an effort is made to be as comprehensive as possible in order to ensure that all relevant studies, published and unpublished, are included in the review and, thus, conclusions are based on this all-inclusive knowledge base. The second type of coverage consists of presenting materials that are representative of most other works in a given field or area. Often authors who adopt this strategy will search for relevant articles in a small number of top-tier journals in a field ( Paré et al., 2015 ). In the third strategy, the review team concentrates on prior works that have been central or pivotal to a particular topic. This may include empirical studies or conceptual papers that initiated a line of investigation, changed how problems or questions were framed, introduced new methods or concepts, or engendered important debate ( Cooper, 1988 ). Screening for inclusion: The following step consists of evaluating the applicability of the material identified in the preceding step ( Levy & Ellis, 2006 ; vom Brocke et al., 2009 ). Once a group of potential studies has been identified, members of the review team must screen them to determine their relevance ( Petticrew & Roberts, 2006 ). A set of predetermined rules provides a basis for including or excluding certain studies. This exercise requires a significant investment on the part of researchers, who must ensure enhanced objectivity and avoid biases or mistakes. As discussed later in this chapter, for certain types of reviews there must be at least two independent reviewers involved in the screening process and a procedure to resolve disagreements must also be in place ( Liberati et al., 2009 ; Shea et al., 2009 ). Assessing the quality of primary studies: In addition to screening material for inclusion, members of the review team may need to assess the scientific quality of the selected studies, that is, appraise the rigour of the research design and methods. Such formal assessment, which is usually conducted independently by at least two coders, helps members of the review team refine which studies to include in the final sample, determine whether or not the differences in quality may affect their conclusions, or guide how they analyze the data and interpret the findings ( Petticrew & Roberts, 2006 ). Ascribing quality scores to each primary study or considering through domain-based evaluations which study components have or have not been designed and executed appropriately makes it possible to reflect on the extent to which the selected study addresses possible biases and maximizes validity ( Shea et al., 2009 ). Extracting data: The following step involves gathering or extracting applicable information from each primary study included in the sample and deciding what is relevant to the problem of interest ( Cooper & Hedges, 2009 ). Indeed, the type of data that should be recorded mainly depends on the initial research questions ( Okoli & Schabram, 2010 ). However, important information may also be gathered about how, when, where and by whom the primary study was conducted, the research design and methods, or qualitative/quantitative results ( Cooper & Hedges, 2009 ). Analyzing and synthesizing data : As a final step, members of the review team must collate, summarize, aggregate, organize, and compare the evidence extracted from the included studies. The extracted data must be presented in a meaningful way that suggests a new contribution to the extant literature ( Jesson et al., 2011 ). Webster and Watson (2002) warn researchers that literature reviews should be much more than lists of papers and should provide a coherent lens to make sense of extant knowledge on a given topic. There exist several methods and techniques for synthesizing quantitative (e.g., frequency analysis, meta-analysis) and qualitative (e.g., grounded theory, narrative analysis, meta-ethnography) evidence ( Dixon-Woods, Agarwal, Jones, Young, & Sutton, 2005 ; Thomas & Harden, 2008 ).

9.3. Types of Review Articles and Brief Illustrations

EHealth researchers have at their disposal a number of approaches and methods for making sense out of existing literature, all with the purpose of casting current research findings into historical contexts or explaining contradictions that might exist among a set of primary research studies conducted on a particular topic. Our classification scheme is largely inspired from Paré and colleagues’ (2015) typology. Below we present and illustrate those review types that we feel are central to the growth and development of the eHealth domain.

9.3.1. Narrative Reviews

The narrative review is the “traditional” way of reviewing the extant literature and is skewed towards a qualitative interpretation of prior knowledge ( Sylvester et al., 2013 ). Put simply, a narrative review attempts to summarize or synthesize what has been written on a particular topic but does not seek generalization or cumulative knowledge from what is reviewed ( Davies, 2000 ; Green et al., 2006 ). Instead, the review team often undertakes the task of accumulating and synthesizing the literature to demonstrate the value of a particular point of view ( Baumeister & Leary, 1997 ). As such, reviewers may selectively ignore or limit the attention paid to certain studies in order to make a point. In this rather unsystematic approach, the selection of information from primary articles is subjective, lacks explicit criteria for inclusion and can lead to biased interpretations or inferences ( Green et al., 2006 ). There are several narrative reviews in the particular eHealth domain, as in all fields, which follow such an unstructured approach ( Silva et al., 2015 ; Paul et al., 2015 ).

Despite these criticisms, this type of review can be very useful in gathering together a volume of literature in a specific subject area and synthesizing it. As mentioned above, its primary purpose is to provide the reader with a comprehensive background for understanding current knowledge and highlighting the significance of new research ( Cronin et al., 2008 ). Faculty like to use narrative reviews in the classroom because they are often more up to date than textbooks, provide a single source for students to reference, and expose students to peer-reviewed literature ( Green et al., 2006 ). For researchers, narrative reviews can inspire research ideas by identifying gaps or inconsistencies in a body of knowledge, thus helping researchers to determine research questions or formulate hypotheses. Importantly, narrative reviews can also be used as educational articles to bring practitioners up to date with certain topics of issues ( Green et al., 2006 ).

Recently, there have been several efforts to introduce more rigour in narrative reviews that will elucidate common pitfalls and bring changes into their publication standards. Information systems researchers, among others, have contributed to advancing knowledge on how to structure a “traditional” review. For instance, Levy and Ellis (2006) proposed a generic framework for conducting such reviews. Their model follows the systematic data processing approach comprised of three steps, namely: (a) literature search and screening; (b) data extraction and analysis; and (c) writing the literature review. They provide detailed and very helpful instructions on how to conduct each step of the review process. As another methodological contribution, vom Brocke et al. (2009) offered a series of guidelines for conducting literature reviews, with a particular focus on how to search and extract the relevant body of knowledge. Last, Bandara, Miskon, and Fielt (2011) proposed a structured, predefined and tool-supported method to identify primary studies within a feasible scope, extract relevant content from identified articles, synthesize and analyze the findings, and effectively write and present the results of the literature review. We highly recommend that prospective authors of narrative reviews consult these useful sources before embarking on their work.

Darlow and Wen (2015) provide a good example of a highly structured narrative review in the eHealth field. These authors synthesized published articles that describe the development process of mobile health ( m-health ) interventions for patients’ cancer care self-management. As in most narrative reviews, the scope of the research questions being investigated is broad: (a) how development of these systems are carried out; (b) which methods are used to investigate these systems; and (c) what conclusions can be drawn as a result of the development of these systems. To provide clear answers to these questions, a literature search was conducted on six electronic databases and Google Scholar . The search was performed using several terms and free text words, combining them in an appropriate manner. Four inclusion and three exclusion criteria were utilized during the screening process. Both authors independently reviewed each of the identified articles to determine eligibility and extract study information. A flow diagram shows the number of studies identified, screened, and included or excluded at each stage of study selection. In terms of contributions, this review provides a series of practical recommendations for m-health intervention development.

9.3.2. Descriptive or Mapping Reviews

The primary goal of a descriptive review is to determine the extent to which a body of knowledge in a particular research topic reveals any interpretable pattern or trend with respect to pre-existing propositions, theories, methodologies or findings ( King & He, 2005 ; Paré et al., 2015 ). In contrast with narrative reviews, descriptive reviews follow a systematic and transparent procedure, including searching, screening and classifying studies ( Petersen, Vakkalanka, & Kuzniarz, 2015 ). Indeed, structured search methods are used to form a representative sample of a larger group of published works ( Paré et al., 2015 ). Further, authors of descriptive reviews extract from each study certain characteristics of interest, such as publication year, research methods, data collection techniques, and direction or strength of research outcomes (e.g., positive, negative, or non-significant) in the form of frequency analysis to produce quantitative results ( Sylvester et al., 2013 ). In essence, each study included in a descriptive review is treated as the unit of analysis and the published literature as a whole provides a database from which the authors attempt to identify any interpretable trends or draw overall conclusions about the merits of existing conceptualizations, propositions, methods or findings ( Paré et al., 2015 ). In doing so, a descriptive review may claim that its findings represent the state of the art in a particular domain ( King & He, 2005 ).

In the fields of health sciences and medical informatics, reviews that focus on examining the range, nature and evolution of a topic area are described by Anderson, Allen, Peckham, and Goodwin (2008) as mapping reviews . Like descriptive reviews, the research questions are generic and usually relate to publication patterns and trends. There is no preconceived plan to systematically review all of the literature although this can be done. Instead, researchers often present studies that are representative of most works published in a particular area and they consider a specific time frame to be mapped.

An example of this approach in the eHealth domain is offered by DeShazo, Lavallie, and Wolf (2009). The purpose of this descriptive or mapping review was to characterize publication trends in the medical informatics literature over a 20-year period (1987 to 2006). To achieve this ambitious objective, the authors performed a bibliometric analysis of medical informatics citations indexed in medline using publication trends, journal frequencies, impact factors, Medical Subject Headings (MeSH) term frequencies, and characteristics of citations. Findings revealed that there were over 77,000 medical informatics articles published during the covered period in numerous journals and that the average annual growth rate was 12%. The MeSH term analysis also suggested a strong interdisciplinary trend. Finally, average impact scores increased over time with two notable growth periods. Overall, patterns in research outputs that seem to characterize the historic trends and current components of the field of medical informatics suggest it may be a maturing discipline (DeShazo et al., 2009).

9.3.3. Scoping Reviews

Scoping reviews attempt to provide an initial indication of the potential size and nature of the extant literature on an emergent topic (Arksey & O’Malley, 2005; Daudt, van Mossel, & Scott, 2013 ; Levac, Colquhoun, & O’Brien, 2010). A scoping review may be conducted to examine the extent, range and nature of research activities in a particular area, determine the value of undertaking a full systematic review (discussed next), or identify research gaps in the extant literature ( Paré et al., 2015 ). In line with their main objective, scoping reviews usually conclude with the presentation of a detailed research agenda for future works along with potential implications for both practice and research.

Unlike narrative and descriptive reviews, the whole point of scoping the field is to be as comprehensive as possible, including grey literature (Arksey & O’Malley, 2005). Inclusion and exclusion criteria must be established to help researchers eliminate studies that are not aligned with the research questions. It is also recommended that at least two independent coders review abstracts yielded from the search strategy and then the full articles for study selection ( Daudt et al., 2013 ). The synthesized evidence from content or thematic analysis is relatively easy to present in tabular form (Arksey & O’Malley, 2005; Thomas & Harden, 2008 ).

One of the most highly cited scoping reviews in the eHealth domain was published by Archer, Fevrier-Thomas, Lokker, McKibbon, and Straus (2011) . These authors reviewed the existing literature on personal health record ( phr ) systems including design, functionality, implementation, applications, outcomes, and benefits. Seven databases were searched from 1985 to March 2010. Several search terms relating to phr s were used during this process. Two authors independently screened titles and abstracts to determine inclusion status. A second screen of full-text articles, again by two independent members of the research team, ensured that the studies described phr s. All in all, 130 articles met the criteria and their data were extracted manually into a database. The authors concluded that although there is a large amount of survey, observational, cohort/panel, and anecdotal evidence of phr benefits and satisfaction for patients, more research is needed to evaluate the results of phr implementations. Their in-depth analysis of the literature signalled that there is little solid evidence from randomized controlled trials or other studies through the use of phr s. Hence, they suggested that more research is needed that addresses the current lack of understanding of optimal functionality and usability of these systems, and how they can play a beneficial role in supporting patient self-management ( Archer et al., 2011 ).

9.3.4. Forms of Aggregative Reviews

Healthcare providers, practitioners, and policy-makers are nowadays overwhelmed with large volumes of information, including research-based evidence from numerous clinical trials and evaluation studies, assessing the effectiveness of health information technologies and interventions ( Ammenwerth & de Keizer, 2004 ; Deshazo et al., 2009 ). It is unrealistic to expect that all these disparate actors will have the time, skills, and necessary resources to identify the available evidence in the area of their expertise and consider it when making decisions. Systematic reviews that involve the rigorous application of scientific strategies aimed at limiting subjectivity and bias (i.e., systematic and random errors) can respond to this challenge.

Systematic reviews attempt to aggregate, appraise, and synthesize in a single source all empirical evidence that meet a set of previously specified eligibility criteria in order to answer a clearly formulated and often narrow research question on a particular topic of interest to support evidence-based practice ( Liberati et al., 2009 ). They adhere closely to explicit scientific principles ( Liberati et al., 2009 ) and rigorous methodological guidelines (Higgins & Green, 2008) aimed at reducing random and systematic errors that can lead to deviations from the truth in results or inferences. The use of explicit methods allows systematic reviews to aggregate a large body of research evidence, assess whether effects or relationships are in the same direction and of the same general magnitude, explain possible inconsistencies between study results, and determine the strength of the overall evidence for every outcome of interest based on the quality of included studies and the general consistency among them ( Cook, Mulrow, & Haynes, 1997 ). The main procedures of a systematic review involve:

• Formulating a review question and developing a search strategy based on explicit inclusion criteria for the identification of eligible studies (usually described in the context of a detailed review protocol).
• Searching for eligible studies using multiple databases and information sources, including grey literature sources, without any language restrictions.
• Selecting studies, extracting data, and assessing risk of bias in a duplicate manner using two independent reviewers to avoid random or systematic errors in the process.
• Analyzing data using quantitative or qualitative methods.
• Presenting results in summary of findings tables.
• Interpreting results and drawing conclusions.

Many systematic reviews, but not all, use statistical methods to combine the results of independent studies into a single quantitative estimate or summary effect size. Known as meta-analyses , these reviews use specific data extraction and statistical techniques (e.g., network, frequentist, or Bayesian meta-analyses) to calculate from each study by outcome of interest an effect size along with a confidence interval that reflects the degree of uncertainty behind the point estimate of effect ( Borenstein, Hedges, Higgins, & Rothstein, 2009 ; Deeks, Higgins, & Altman, 2008 ). Subsequently, they use fixed or random-effects analysis models to combine the results of the included studies, assess statistical heterogeneity, and calculate a weighted average of the effect estimates from the different studies, taking into account their sample sizes. The summary effect size is a value that reflects the average magnitude of the intervention effect for a particular outcome of interest or, more generally, the strength of a relationship between two variables across all studies included in the systematic review. By statistically combining data from multiple studies, meta-analyses can create more precise and reliable estimates of intervention effects than those derived from individual studies alone, when these are examined independently as discrete sources of information.

The review by Gurol-Urganci, de Jongh, Vodopivec-Jamsek, Atun, and Car (2013) on the effects of mobile phone messaging reminders for attendance at healthcare appointments is an illustrative example of a high-quality systematic review with meta-analysis. Missed appointments are a major cause of inefficiency in healthcare delivery with substantial monetary costs to health systems. These authors sought to assess whether mobile phone-based appointment reminders delivered through Short Message Service ( sms ) or Multimedia Messaging Service ( mms ) are effective in improving rates of patient attendance and reducing overall costs. To this end, they conducted a comprehensive search on multiple databases using highly sensitive search strategies without language or publication-type restrictions to identify all rct s that are eligible for inclusion. In order to minimize the risk of omitting eligible studies not captured by the original search, they supplemented all electronic searches with manual screening of trial registers and references contained in the included studies. Study selection, data extraction, and risk of bias assessments were performed inde­­pen­dently by two coders using standardized methods to ensure consistency and to eliminate potential errors. Findings from eight rct s involving 6,615 participants were pooled into meta-analyses to calculate the magnitude of effects that mobile text message reminders have on the rate of attendance at healthcare appointments compared to no reminders and phone call reminders.

Meta-analyses are regarded as powerful tools for deriving meaningful conclusions. However, there are situations in which it is neither reasonable nor appropriate to pool studies together using meta-analytic methods simply because there is extensive clinical heterogeneity between the included studies or variation in measurement tools, comparisons, or outcomes of interest. In these cases, systematic reviews can use qualitative synthesis methods such as vote counting, content analysis, classification schemes and tabulations, as an alternative approach to narratively synthesize the results of the independent studies included in the review. This form of review is known as qualitative systematic review.

A rigorous example of one such review in the eHealth domain is presented by Mickan, Atherton, Roberts, Heneghan, and Tilson (2014) on the use of handheld computers by healthcare professionals and their impact on access to information and clinical decision-making. In line with the methodological guide­lines for systematic reviews, these authors: (a) developed and registered with prospero ( www.crd.york.ac.uk/ prospero / ) an a priori review protocol; (b) conducted comprehensive searches for eligible studies using multiple databases and other supplementary strategies (e.g., forward searches); and (c) subsequently carried out study selection, data extraction, and risk of bias assessments in a duplicate manner to eliminate potential errors in the review process. Heterogeneity between the included studies in terms of reported outcomes and measures precluded the use of meta-analytic methods. To this end, the authors resorted to using narrative analysis and synthesis to describe the effectiveness of handheld computers on accessing information for clinical knowledge, adherence to safety and clinical quality guidelines, and diagnostic decision-making.

In recent years, the number of systematic reviews in the field of health informatics has increased considerably. Systematic reviews with discordant findings can cause great confusion and make it difficult for decision-makers to interpret the review-level evidence ( Moher, 2013 ). Therefore, there is a growing need for appraisal and synthesis of prior systematic reviews to ensure that decision-making is constantly informed by the best available accumulated evidence. Umbrella reviews , also known as overviews of systematic reviews, are tertiary types of evidence synthesis that aim to accomplish this; that is, they aim to compare and contrast findings from multiple systematic reviews and meta-analyses ( Becker & Oxman, 2008 ). Umbrella reviews generally adhere to the same principles and rigorous methodological guidelines used in systematic reviews. However, the unit of analysis in umbrella reviews is the systematic review rather than the primary study ( Becker & Oxman, 2008 ). Unlike systematic reviews that have a narrow focus of inquiry, umbrella reviews focus on broader research topics for which there are several potential interventions ( Smith, Devane, Begley, & Clarke, 2011 ). A recent umbrella review on the effects of home telemonitoring interventions for patients with heart failure critically appraised, compared, and synthesized evidence from 15 systematic reviews to investigate which types of home telemonitoring technologies and forms of interventions are more effective in reducing mortality and hospital admissions ( Kitsiou, Paré, & Jaana, 2015 ).

9.3.5. Realist Reviews

Realist reviews are theory-driven interpretative reviews developed to inform, enhance, or supplement conventional systematic reviews by making sense of heterogeneous evidence about complex interventions applied in diverse contexts in a way that informs policy decision-making ( Greenhalgh, Wong, Westhorp, & Pawson, 2011 ). They originated from criticisms of positivist systematic reviews which centre on their “simplistic” underlying assumptions ( Oates, 2011 ). As explained above, systematic reviews seek to identify causation. Such logic is appropriate for fields like medicine and education where findings of randomized controlled trials can be aggregated to see whether a new treatment or intervention does improve outcomes. However, many argue that it is not possible to establish such direct causal links between interventions and outcomes in fields such as social policy, management, and information systems where for any intervention there is unlikely to be a regular or consistent outcome ( Oates, 2011 ; Pawson, 2006 ; Rousseau, Manning, & Denyer, 2008 ).

To circumvent these limitations, Pawson, Greenhalgh, Harvey, and Walshe (2005) have proposed a new approach for synthesizing knowledge that seeks to unpack the mechanism of how “complex interventions” work in particular contexts. The basic research question — what works? — which is usually associated with systematic reviews changes to: what is it about this intervention that works, for whom, in what circumstances, in what respects and why? Realist reviews have no particular preference for either quantitative or qualitative evidence. As a theory-building approach, a realist review usually starts by articulating likely underlying mechanisms and then scrutinizes available evidence to find out whether and where these mechanisms are applicable ( Shepperd et al., 2009 ). Primary studies found in the extant literature are viewed as case studies which can test and modify the initial theories ( Rousseau et al., 2008 ).

The main objective pursued in the realist review conducted by Otte-Trojel, de Bont, Rundall, and van de Klundert (2014) was to examine how patient portals contribute to health service delivery and patient outcomes. The specific goals were to investigate how outcomes are produced and, most importantly, how variations in outcomes can be explained. The research team started with an exploratory review of background documents and research studies to identify ways in which patient portals may contribute to health service delivery and patient outcomes. The authors identified six main ways which represent “educated guesses” to be tested against the data in the evaluation studies. These studies were identified through a formal and systematic search in four databases between 2003 and 2013. Two members of the research team selected the articles using a pre-established list of inclusion and exclusion criteria and following a two-step procedure. The authors then extracted data from the selected articles and created several tables, one for each outcome category. They organized information to bring forward those mechanisms where patient portals contribute to outcomes and the variation in outcomes across different contexts.

9.3.6. Critical Reviews

Lastly, critical reviews aim to provide a critical evaluation and interpretive analysis of existing literature on a particular topic of interest to reveal strengths, weaknesses, contradictions, controversies, inconsistencies, and/or other important issues with respect to theories, hypotheses, research methods or results ( Baumeister & Leary, 1997 ; Kirkevold, 1997 ). Unlike other review types, critical reviews attempt to take a reflective account of the research that has been done in a particular area of interest, and assess its credibility by using appraisal instruments or critical interpretive methods. In this way, critical reviews attempt to constructively inform other scholars about the weaknesses of prior research and strengthen knowledge development by giving focus and direction to studies for further improvement ( Kirkevold, 1997 ).

Kitsiou, Paré, and Jaana (2013) provide an example of a critical review that assessed the methodological quality of prior systematic reviews of home telemonitoring studies for chronic patients. The authors conducted a comprehensive search on multiple databases to identify eligible reviews and subsequently used a validated instrument to conduct an in-depth quality appraisal. Results indicate that the majority of systematic reviews in this particular area suffer from important methodological flaws and biases that impair their internal validity and limit their usefulness for clinical and decision-making purposes. To this end, they provide a number of recommendations to strengthen knowledge development towards improving the design and execution of future reviews on home telemonitoring.

9.4. Summary

Table 9.1 outlines the main types of literature reviews that were described in the previous sub-sections and summarizes the main characteristics that distinguish one review type from another. It also includes key references to methodological guidelines and useful sources that can be used by eHealth scholars and researchers for planning and developing reviews.

Typology of Literature Reviews (adapted from Paré et al., 2015).

As shown in Table 9.1 , each review type addresses different kinds of research questions or objectives, which subsequently define and dictate the methods and approaches that need to be used to achieve the overarching goal(s) of the review. For example, in the case of narrative reviews, there is greater flexibility in searching and synthesizing articles ( Green et al., 2006 ). Researchers are often relatively free to use a diversity of approaches to search, identify, and select relevant scientific articles, describe their operational characteristics, present how the individual studies fit together, and formulate conclusions. On the other hand, systematic reviews are characterized by their high level of systematicity, rigour, and use of explicit methods, based on an “a priori” review plan that aims to minimize bias in the analysis and synthesis process (Higgins & Green, 2008). Some reviews are exploratory in nature (e.g., scoping/mapping reviews), whereas others may be conducted to discover patterns (e.g., descriptive reviews) or involve a synthesis approach that may include the critical analysis of prior research ( Paré et al., 2015 ). Hence, in order to select the most appropriate type of review, it is critical to know before embarking on a review project, why the research synthesis is conducted and what type of methods are best aligned with the pursued goals.

9.5. Concluding Remarks

In light of the increased use of evidence-based practice and research generating stronger evidence ( Grady et al., 2011 ; Lyden et al., 2013 ), review articles have become essential tools for summarizing, synthesizing, integrating or critically appraising prior knowledge in the eHealth field. As mentioned earlier, when rigorously conducted review articles represent powerful information sources for eHealth scholars and practitioners looking for state-of-the-art evidence. The typology of literature reviews we used herein will allow eHealth researchers, graduate students and practitioners to gain a better understanding of the similarities and differences between review types.

We must stress that this classification scheme does not privilege any specific type of review as being of higher quality than another ( Paré et al., 2015 ). As explained above, each type of review has its own strengths and limitations. Having said that, we realize that the methodological rigour of any review — be it qualitative, quantitative or mixed — is a critical aspect that should be considered seriously by prospective authors. In the present context, the notion of rigour refers to the reliability and validity of the review process described in section 9.2. For one thing, reliability is related to the reproducibility of the review process and steps, which is facilitated by a comprehensive documentation of the literature search process, extraction, coding and analysis performed in the review. Whether the search is comprehensive or not, whether it involves a methodical approach for data extraction and synthesis or not, it is important that the review documents in an explicit and transparent manner the steps and approach that were used in the process of its development. Next, validity characterizes the degree to which the review process was conducted appropriately. It goes beyond documentation and reflects decisions related to the selection of the sources, the search terms used, the period of time covered, the articles selected in the search, and the application of backward and forward searches ( vom Brocke et al., 2009 ). In short, the rigour of any review article is reflected by the explicitness of its methods (i.e., transparency) and the soundness of the approach used. We refer those interested in the concepts of rigour and quality to the work of Templier and Paré (2015) which offers a detailed set of methodological guidelines for conducting and evaluating various types of review articles.

To conclude, our main objective in this chapter was to demystify the various types of literature reviews that are central to the continuous development of the eHealth field. It is our hope that our descriptive account will serve as a valuable source for those conducting, evaluating or using reviews in this important and growing domain.

• Ammenwerth E., de Keizer N. An inventory of evaluation studies of information technology in health care. Trends in evaluation research, 1982-2002. International Journal of Medical Informatics. 2004; 44 (1):44–56. [ PubMed : 15778794 ]
• Anderson S., Allen P., Peckham S., Goodwin N. Asking the right questions: scoping studies in the commissioning of research on the organisation and delivery of health services. Health Research Policy and Systems. 2008; 6 (7):1–12. [ PMC free article : PMC2500008 ] [ PubMed : 18613961 ] [ CrossRef ]
• Archer N., Fevrier-Thomas U., Lokker C., McKibbon K. A., Straus S.E. Personal health records: a scoping review. Journal of American Medical Informatics Association. 2011; 18 (4):515–522. [ PMC free article : PMC3128401 ] [ PubMed : 21672914 ]
• Arksey H., O’Malley L. Scoping studies: towards a methodological framework. International Journal of Social Research Methodology. 2005; 8 (1):19–32.
• A systematic, tool-supported method for conducting literature reviews in information systems. Paper presented at the Proceedings of the 19th European Conference on Information Systems ( ecis 2011); June 9 to 11; Helsinki, Finland. 2011.
• Baumeister R. F., Leary M.R. Writing narrative literature reviews. Review of General Psychology. 1997; 1 (3):311–320.
• Becker L. A., Oxman A.D. In: Cochrane handbook for systematic reviews of interventions. Higgins J. P. T., Green S., editors. Hoboken, nj : John Wiley & Sons, Ltd; 2008. Overviews of reviews; pp. 607–631.
• Borenstein M., Hedges L., Higgins J., Rothstein H. Introduction to meta-analysis. Hoboken, nj : John Wiley & Sons Inc; 2009.
• Cook D. J., Mulrow C. D., Haynes B. Systematic reviews: Synthesis of best evidence for clinical decisions. Annals of Internal Medicine. 1997; 126 (5):376–380. [ PubMed : 9054282 ]
• Cooper H., Hedges L.V. In: The handbook of research synthesis and meta-analysis. 2nd ed. Cooper H., Hedges L. V., Valentine J. C., editors. New York: Russell Sage Foundation; 2009. Research synthesis as a scientific process; pp. 3–17.
• Cooper H. M. Organizing knowledge syntheses: A taxonomy of literature reviews. Knowledge in Society. 1988; 1 (1):104–126.
• Cronin P., Ryan F., Coughlan M. Undertaking a literature review: a step-by-step approach. British Journal of Nursing. 2008; 17 (1):38–43. [ PubMed : 18399395 ]
• Darlow S., Wen K.Y. Development testing of mobile health interventions for cancer patient self-management: A review. Health Informatics Journal. 2015 (online before print). [ PubMed : 25916831 ] [ CrossRef ]
• Daudt H. M., van Mossel C., Scott S.J. Enhancing the scoping study methodology: a large, inter-professional team’s experience with Arksey and O’Malley’s framework. bmc Medical Research Methodology. 2013; 13 :48. [ PMC free article : PMC3614526 ] [ PubMed : 23522333 ] [ CrossRef ]
• Davies P. The relevance of systematic reviews to educational policy and practice. Oxford Review of Education. 2000; 26 (3-4):365–378.
• Deeks J. J., Higgins J. P. T., Altman D.G. In: Cochrane handbook for systematic reviews of interventions. Higgins J. P. T., Green S., editors. Hoboken, nj : John Wiley & Sons, Ltd; 2008. Analysing data and undertaking meta-analyses; pp. 243–296.
• Deshazo J. P., Lavallie D. L., Wolf F.M. Publication trends in the medical informatics literature: 20 years of “Medical Informatics” in mesh . bmc Medical Informatics and Decision Making. 2009; 9 :7. [ PMC free article : PMC2652453 ] [ PubMed : 19159472 ] [ CrossRef ]
• Dixon-Woods M., Agarwal S., Jones D., Young B., Sutton A. Synthesising qualitative and quantitative evidence: a review of possible methods. Journal of Health Services Research and Policy. 2005; 10 (1):45–53. [ PubMed : 15667704 ]
• Finfgeld-Connett D., Johnson E.D. Literature search strategies for conducting knowledge-building and theory-generating qualitative systematic reviews. Journal of Advanced Nursing. 2013; 69 (1):194–204. [ PMC free article : PMC3424349 ] [ PubMed : 22591030 ]
• Grady B., Myers K. M., Nelson E. L., Belz N., Bennett L., Carnahan L. … Guidelines Working Group. Evidence-based practice for telemental health. Telemedicine Journal and E Health. 2011; 17 (2):131–148. [ PubMed : 21385026 ]
• Green B. N., Johnson C. D., Adams A. Writing narrative literature reviews for peer-reviewed journals: secrets of the trade. Journal of Chiropractic Medicine. 2006; 5 (3):101–117. [ PMC free article : PMC2647067 ] [ PubMed : 19674681 ]
• Greenhalgh T., Wong G., Westhorp G., Pawson R. Protocol–realist and meta-narrative evidence synthesis: evolving standards ( rameses ). bmc Medical Research Methodology. 2011; 11 :115. [ PMC free article : PMC3173389 ] [ PubMed : 21843376 ]
• Gurol-Urganci I., de Jongh T., Vodopivec-Jamsek V., Atun R., Car J. Mobile phone messaging reminders for attendance at healthcare appointments. Cochrane Database System Review. 2013; 12 cd 007458. [ PMC free article : PMC6485985 ] [ PubMed : 24310741 ] [ CrossRef ]
• Hart C. Doing a literature review: Releasing the social science research imagination. London: SAGE Publications; 1998.
• Higgins J. P. T., Green S., editors. Cochrane handbook for systematic reviews of interventions: Cochrane book series. Hoboken, nj : Wiley-Blackwell; 2008.
• Jesson J., Matheson L., Lacey F.M. Doing your literature review: traditional and systematic techniques. Los Angeles & London: SAGE Publications; 2011.
• King W. R., He J. Understanding the role and methods of meta-analysis in IS research. Communications of the Association for Information Systems. 2005; 16 :1.
• Kirkevold M. Integrative nursing research — an important strategy to further the development of nursing science and nursing practice. Journal of Advanced Nursing. 1997; 25 (5):977–984. [ PubMed : 9147203 ]
• Kitchenham B., Charters S. ebse Technical Report Version 2.3. Keele & Durham. uk : Keele University & University of Durham; 2007. Guidelines for performing systematic literature reviews in software engineering.
• Kitsiou S., Paré G., Jaana M. Systematic reviews and meta-analyses of home telemonitoring interventions for patients with chronic diseases: a critical assessment of their methodological quality. Journal of Medical Internet Research. 2013; 15 (7):e150. [ PMC free article : PMC3785977 ] [ PubMed : 23880072 ]
• Kitsiou S., Paré G., Jaana M. Effects of home telemonitoring interventions on patients with chronic heart failure: an overview of systematic reviews. Journal of Medical Internet Research. 2015; 17 (3):e63. [ PMC free article : PMC4376138 ] [ PubMed : 25768664 ]
• Levac D., Colquhoun H., O’Brien K. K. Scoping studies: advancing the methodology. Implementation Science. 2010; 5 (1):69. [ PMC free article : PMC2954944 ] [ PubMed : 20854677 ]
• Levy Y., Ellis T.J. A systems approach to conduct an effective literature review in support of information systems research. Informing Science. 2006; 9 :181–211.
• Liberati A., Altman D. G., Tetzlaff J., Mulrow C., Gøtzsche P. C., Ioannidis J. P. A. et al. Moher D. The prisma statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: Explanation and elaboration. Annals of Internal Medicine. 2009; 151 (4):W-65. [ PubMed : 19622512 ]
• Lyden J. R., Zickmund S. L., Bhargava T. D., Bryce C. L., Conroy M. B., Fischer G. S. et al. McTigue K. M. Implementing health information technology in a patient-centered manner: Patient experiences with an online evidence-based lifestyle intervention. Journal for Healthcare Quality. 2013; 35 (5):47–57. [ PubMed : 24004039 ]
• Mickan S., Atherton H., Roberts N. W., Heneghan C., Tilson J.K. Use of handheld computers in clinical practice: a systematic review. bmc Medical Informatics and Decision Making. 2014; 14 :56. [ PMC free article : PMC4099138 ] [ PubMed : 24998515 ]
• Moher D. The problem of duplicate systematic reviews. British Medical Journal. 2013; 347 (5040) [ PubMed : 23945367 ] [ CrossRef ]
• Montori V. M., Wilczynski N. L., Morgan D., Haynes R. B., Hedges T. Systematic reviews: a cross-sectional study of location and citation counts. bmc Medicine. 2003; 1 :2. [ PMC free article : PMC281591 ] [ PubMed : 14633274 ]
• Mulrow C. D. The medical review article: state of the science. Annals of Internal Medicine. 1987; 106 (3):485–488. [ PubMed : 3813259 ] [ CrossRef ]
• Evidence-based information systems: A decade later. Proceedings of the European Conference on Information Systems ; 2011. Retrieved from http://aisel ​.aisnet.org/cgi/viewcontent ​.cgi?article ​=1221&context ​=ecis2011 .
• Okoli C., Schabram K. A guide to conducting a systematic literature review of information systems research. ssrn Electronic Journal. 2010
• Otte-Trojel T., de Bont A., Rundall T. G., van de Klundert J. How outcomes are achieved through patient portals: a realist review. Journal of American Medical Informatics Association. 2014; 21 (4):751–757. [ PMC free article : PMC4078283 ] [ PubMed : 24503882 ]
• Paré G., Trudel M.-C., Jaana M., Kitsiou S. Synthesizing information systems knowledge: A typology of literature reviews. Information & Management. 2015; 52 (2):183–199.
• Patsopoulos N. A., Analatos A. A., Ioannidis J.P. A. Relative citation impact of various study designs in the health sciences. Journal of the American Medical Association. 2005; 293 (19):2362–2366. [ PubMed : 15900006 ]
• Paul M. M., Greene C. M., Newton-Dame R., Thorpe L. E., Perlman S. E., McVeigh K. H., Gourevitch M.N. The state of population health surveillance using electronic health records: A narrative review. Population Health Management. 2015; 18 (3):209–216. [ PubMed : 25608033 ]
• Pawson R. Evidence-based policy: a realist perspective. London: SAGE Publications; 2006.
• Pawson R., Greenhalgh T., Harvey G., Walshe K. Realist review—a new method of systematic review designed for complex policy interventions. Journal of Health Services Research & Policy. 2005; 10 (Suppl 1):21–34. [ PubMed : 16053581 ]
• Petersen K., Vakkalanka S., Kuzniarz L. Guidelines for conducting systematic mapping studies in software engineering: An update. Information and Software Technology. 2015; 64 :1–18.
• Petticrew M., Roberts H. Systematic reviews in the social sciences: A practical guide. Malden, ma : Blackwell Publishing Co; 2006.
• Rousseau D. M., Manning J., Denyer D. Evidence in management and organizational science: Assembling the field’s full weight of scientific knowledge through syntheses. The Academy of Management Annals. 2008; 2 (1):475–515.
• Rowe F. What literature review is not: diversity, boundaries and recommendations. European Journal of Information Systems. 2014; 23 (3):241–255.
• Shea B. J., Hamel C., Wells G. A., Bouter L. M., Kristjansson E., Grimshaw J. et al. Boers M. amstar is a reliable and valid measurement tool to assess the methodological quality of systematic reviews. Journal of Clinical Epidemiology. 2009; 62 (10):1013–1020. [ PubMed : 19230606 ]
• Shepperd S., Lewin S., Straus S., Clarke M., Eccles M. P., Fitzpatrick R. et al. Sheikh A. Can we systematically review studies that evaluate complex interventions? PLoS Medicine. 2009; 6 (8):e1000086. [ PMC free article : PMC2717209 ] [ PubMed : 19668360 ]
• Silva B. M., Rodrigues J. J., de la Torre Díez I., López-Coronado M., Saleem K. Mobile-health: A review of current state in 2015. Journal of Biomedical Informatics. 2015; 56 :265–272. [ PubMed : 26071682 ]
• Smith V., Devane D., Begley C., Clarke M. Methodology in conducting a systematic review of systematic reviews of healthcare interventions. bmc Medical Research Methodology. 2011; 11 (1):15. [ PMC free article : PMC3039637 ] [ PubMed : 21291558 ]
• Sylvester A., Tate M., Johnstone D. Beyond synthesis: re-presenting heterogeneous research literature. Behaviour & Information Technology. 2013; 32 (12):1199–1215.
• Templier M., Paré G. A framework for guiding and evaluating literature reviews. Communications of the Association for Information Systems. 2015; 37 (6):112–137.
• Thomas J., Harden A. Methods for the thematic synthesis of qualitative research in systematic reviews. bmc Medical Research Methodology. 2008; 8 (1):45. [ PMC free article : PMC2478656 ] [ PubMed : 18616818 ]
• Reconstructing the giant: on the importance of rigour in documenting the literature search process. Paper presented at the Proceedings of the 17th European Conference on Information Systems ( ecis 2009); Verona, Italy. 2009.
• Webster J., Watson R.T. Analyzing the past to prepare for the future: Writing a literature review. Management Information Systems Quarterly. 2002; 26 (2):11.
• Whitlock E. P., Lin J. S., Chou R., Shekelle P., Robinson K.A. Using existing systematic reviews in complex systematic reviews. Annals of Internal Medicine. 2008; 148 (10):776–782. [ PubMed : 18490690 ]

This publication is licensed under a Creative Commons License, Attribution-Noncommercial 4.0 International License (CC BY-NC 4.0): see https://creativecommons.org/licenses/by-nc/4.0/

• Cite this Page Paré G, Kitsiou S. Chapter 9 Methods for Literature Reviews. In: Lau F, Kuziemsky C, editors. Handbook of eHealth Evaluation: An Evidence-based Approach [Internet]. Victoria (BC): University of Victoria; 2017 Feb 27.
• PDF version of this title (4.5M)
• Disable Glossary Links

In this Page

• Introduction
• Overview of the Literature Review Process and Steps
• Types of Review Articles and Brief Illustrations
• Concluding Remarks

Related information

• PMC PubMed Central citations
• PubMed Links to PubMed

Recent Activity

• Chapter 9 Methods for Literature Reviews - Handbook of eHealth Evaluation: An Ev... Chapter 9 Methods for Literature Reviews - Handbook of eHealth Evaluation: An Evidence-based Approach

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

Connect with NLM

National Library of Medicine 8600 Rockville Pike Bethesda, MD 20894

Web Policies FOIA HHS Vulnerability Disclosure

Help Accessibility Careers

Literature Review: Purpose of a Literature Review

• Literature Review
• Purpose of a Literature Review
• Work in Progress
• Compiling & Writing
• Books, Articles, & Web Pages
• Types of Literature Reviews
• Departmental Differences
• Citation Styles & Plagiarism
• Know the Difference! Systematic Review vs. Literature Review

The purpose of a literature review is to:

• Provide a foundation of knowledge on a topic
• Identify areas of prior scholarship to prevent duplication and give credit to other researchers
• Identify inconstancies: gaps in research, conflicts in previous studies, open questions left from other research
• Identify the need for additional research (justifying your research)
• Identify the relationship of works in the context of their contribution to the topic and other works
• Place your own research within the context of existing literature, making a case for why further study is needed.

Videos & Tutorials

VIDEO: What is the role of a literature review in research? What's it mean to "review" the literature? Get the big picture of what to expect as part of the process. This video is published under a Creative Commons 3.0 BY-NC-SA US license. License, credits, and contact information can be found here: https://www.lib.ncsu.edu/tutorials/litreview/

Elements in a Literature Review

• Elements in a Literature Review txt of infographic
• << Previous: Literature Review
• Next: Searching >>
• Last Updated: Oct 19, 2023 12:07 PM
• URL: https://uscupstate.libguides.com/Literature_Review

Organizing and Creating Information

• Citation and Attribution

What Is a Literature Review?

Review the literature, write the literature review, further reading, learning objectives, attribution.

This guide is designed to:

• Identify the sections and purpose of a literature review in academic writing
• Review practical strategies and organizational methods for preparing a literature review

A literature review is a summary and synthesis of scholarly research on a specific topic. It should answer questions such as:

• What research has been done on the topic?
• Who are the key researchers and experts in the field?
• What are the common theories and methodologies?
• Are there challenges, controversies, and contradictions?
• Are there gaps in the research that your approach addresses?

The process of reviewing existing research allows you to fine-tune your research question and contextualize your own work. Preparing a literature review is a cyclical process. You may find that the research question you begin with evolves as you learn more about the topic.

Once you have defined your research question , focus on learning what other scholars have written on the topic.

In order to  do a thorough search of the literature  on the topic, define the basic criteria:

• Databases and journals: Look at the  subject guide  related to your topic for recommended databases. Review the  tutorial on finding articles  for tips. 
• Books: Search BruKnow, the Library's catalog. Steps to searching ebooks are covered in the  Finding Ebooks tutorial .
• What time period should it cover? Is currency important?
• Do I know of primary and secondary sources that I can use as a way to find other information?
• What should I be aware of when looking at popular, trade, and scholarly resources ? 

One strategy is to review bibliographies for sources that relate to your interest. For more on this technique, look at the tutorial on finding articles when you have a citation .

Tip: Use a Synthesis Matrix

As you read sources, themes will emerge that will help you to organize the review. You can use a simple Synthesis Matrix to track your notes as you read. From this work, a concept map emerges that provides an overview of the literature and ways in which it connects. Working with Zotero to capture the citations, you build the structure for writing your literature review.

How do I know when I am done?

A key indicator for knowing when you are done is running into the same articles and materials. With no new information being uncovered, you are likely exhausting your current search and should modify search terms or search different catalogs or databases. It is also possible that you have reached a point when you can start writing the literature review.

Tip: Manage Your Citations

These citation management tools also create citations, footnotes, and bibliographies with just a few clicks:

Zotero Tutorial

Endnote Tutorial

Your literature review should be focused on the topic defined in your research question. It should be written in a logical, structured way and maintain an objective perspective and use a formal voice.

Review the Summary Table you created for themes and connecting ideas. Use the following guidelines to prepare an outline of the main points you want to make. 

• Synthesize previous research on the topic.
• Aim to include both summary and synthesis.
• Include literature that supports your research question as well as that which offers a different perspective.
• Avoid relying on one author or publication too heavily.
• Select an organizational structure, such as chronological, methodological, and thematic.

The three elements of a literature review are introduction, body, and conclusion.

Introduction

• Define the topic of the literature review, including any terminology.
• Introduce the central theme and organization of the literature review.
• Summarize the state of research on the topic.
• Frame the literature review with your research question.
• Focus on ways to have the body of literature tell its own story. Do not add your own interpretations at this point.
• Look for patterns and find ways to tie the pieces together.
• Summarize instead of quote.
• Weave the points together rather than list summaries of each source.
• Include the most important sources, not everything you have read.
• Summarize the review of the literature.
• Identify areas of further research on the topic.
• Connect the review with your research.
• DeCarlo, M. (2018). 4.1 What is a literature review? In Scientific Inquiry in Social Work. Open Social Work Education. https://scientificinquiryinsocialwork.pressbooks.com/chapter/4-1-what-is-a-literature-review/
• Literature Reviews (n.d.) https://writingcenter.unc.edu/tips-and-tools/literature-reviews/ Accessed Nov. 10, 2021

This guide was designed to: 

• Identify the sections and purpose of a literature review in academic writing 
• Review practical strategies and organizational methods for preparing a literature review​

Content on this page adapted from: 

Frederiksen, L. and Phelps, S. (2017).   Literature Reviews for Education and Nursing Graduate Students.  Licensed CC BY 4.0

• << Previous: EndNote
• Last Updated: Jan 9, 2024 3:05 PM
• URL: https://libguides.brown.edu/organize

Brown University Library  |  Providence, RI 02912  |  (401) 863-2165  |  Contact  |  Comments  |  Library Feedback  |  Site Map

Library Intranet

How to write a literature review introduction (+ examples)

The introduction to a literature review serves as your reader’s guide through your academic work and thought process. Explore the significance of literature review introductions in review papers, academic papers, essays, theses, and dissertations. We delve into the purpose and necessity of these introductions, explore the essential components of literature review introductions, and provide step-by-step guidance on how to craft your own, along with examples.

Why you need an introduction for a literature review

When you need an introduction for a literature review, what to include in a literature review introduction, examples of literature review introductions, steps to write your own literature review introduction.

A literature review is a comprehensive examination of the international academic literature concerning a particular topic. It involves summarizing published works, theories, and concepts while also highlighting gaps and offering critical reflections.

In academic writing , the introduction for a literature review is an indispensable component. Effective academic writing requires proper paragraph structuring to guide your reader through your argumentation. This includes providing an introduction to your literature review.

It is imperative to remember that you should never start sharing your findings abruptly. Even if there isn’t a dedicated introduction section .

Instead, you should always offer some form of introduction to orient the reader and clarify what they can expect.

There are three main scenarios in which you need an introduction for a literature review:

• Academic literature review papers: When your literature review constitutes the entirety of an academic review paper, a more substantial introduction is necessary. This introduction should resemble the standard introduction found in regular academic papers.
• Literature review section in an academic paper or essay: While this section tends to be brief, it’s important to precede the detailed literature review with a few introductory sentences. This helps orient the reader before delving into the literature itself.
• Literature review chapter or section in your thesis/dissertation: Every thesis and dissertation includes a literature review component, which also requires a concise introduction to set the stage for the subsequent review.

You may also like: How to write a fantastic thesis introduction (+15 examples)

It is crucial to customize the content and depth of your literature review introduction according to the specific format of your academic work.

In practical terms, this implies, for instance, that the introduction in an academic literature review paper, especially one derived from a systematic literature review , is quite comprehensive. Particularly compared to the rather brief one or two introductory sentences that are often found at the beginning of a literature review section in a standard academic paper. The introduction to the literature review chapter in a thesis or dissertation again adheres to different standards.

Here’s a structured breakdown based on length and the necessary information:

Academic literature review paper

The introduction of an academic literature review paper, which does not rely on empirical data, often necessitates a more extensive introduction than the brief literature review introductions typically found in empirical papers. It should encompass:

• The research problem: Clearly articulate the problem or question that your literature review aims to address.
• The research gap: Highlight the existing gaps, limitations, or unresolved aspects within the current body of literature related to the research problem.
• The research relevance: Explain why the chosen research problem and its subsequent investigation through a literature review are significant and relevant in your academic field.
• The literature review method: If applicable, describe the methodology employed in your literature review, especially if it is a systematic review or follows a specific research framework.
• The main findings or insights of the literature review: Summarize the key discoveries, insights, or trends that have emerged from your comprehensive review of the literature.
• The main argument of the literature review: Conclude the introduction by outlining the primary argument or statement that your literature review will substantiate, linking it to the research problem and relevance you’ve established.
• Preview of the literature review’s structure: Offer a glimpse into the organization of the literature review paper, acting as a guide for the reader. This overview outlines the subsequent sections of the paper and provides an understanding of what to anticipate.

By addressing these elements, your introduction will provide a clear and structured overview of what readers can expect in your literature review paper.

Regular literature review section in an academic article or essay

Most academic articles or essays incorporate regular literature review sections, often placed after the introduction. These sections serve to establish a scholarly basis for the research or discussion within the paper.

In a standard 8000-word journal article, the literature review section typically spans between 750 and 1250 words. The first few sentences or the first paragraph within this section often serve as an introduction. It should encompass:

• An introduction to the topic: When delving into the academic literature on a specific topic, it’s important to provide a smooth transition that aids the reader in comprehending why certain aspects will be discussed within your literature review.
• The core argument: While literature review sections primarily synthesize the work of other scholars, they should consistently connect to your central argument. This central argument serves as the crux of your message or the key takeaway you want your readers to retain. By positioning it at the outset of the literature review section and systematically substantiating it with evidence, you not only enhance reader comprehension but also elevate overall readability. This primary argument can typically be distilled into 1-2 succinct sentences.

In some cases, you might include:

• Methodology: Details about the methodology used, but only if your literature review employed a specialized method. If your approach involved a broader overview without a systematic methodology, you can omit this section, thereby conserving word count.

By addressing these elements, your introduction will effectively integrate your literature review into the broader context of your academic paper or essay. This will, in turn, assist your reader in seamlessly following your overarching line of argumentation.

Introduction to a literature review chapter in thesis or dissertation

The literature review typically constitutes a distinct chapter within a thesis or dissertation. Often, it is Chapter 2 of a thesis or dissertation.

Some students choose to incorporate a brief introductory section at the beginning of each chapter, including the literature review chapter. Alternatively, others opt to seamlessly integrate the introduction into the initial sentences of the literature review itself. Both approaches are acceptable, provided that you incorporate the following elements:

• Purpose of the literature review and its relevance to the thesis/dissertation research: Explain the broader objectives of the literature review within the context of your research and how it contributes to your thesis or dissertation. Essentially, you’re telling the reader why this literature review is important and how it fits into the larger scope of your academic work.
• Primary argument: Succinctly communicate what you aim to prove, explain, or explore through the review of existing literature. This statement helps guide the reader’s understanding of the review’s purpose and what to expect from it.
• Preview of the literature review’s content: Provide a brief overview of the topics or themes that your literature review will cover. It’s like a roadmap for the reader, outlining the main areas of focus within the review. This preview can help the reader anticipate the structure and organization of your literature review.
• Methodology: If your literature review involved a specific research method, such as a systematic review or meta-analysis, you should briefly describe that methodology. However, this is not always necessary, especially if your literature review is more of a narrative synthesis without a distinct research method.

By addressing these elements, your introduction will empower your literature review to play a pivotal role in your thesis or dissertation research. It will accomplish this by integrating your research into the broader academic literature and providing a solid theoretical foundation for your work.

Comprehending the art of crafting your own literature review introduction becomes significantly more accessible when you have concrete examples to examine. Here, you will find several examples that meet, or in most cases, adhere to the criteria described earlier.

Example 1: An effective introduction for an academic literature review paper

To begin, let’s delve into the introduction of an academic literature review paper. We will examine the paper “How does culture influence innovation? A systematic literature review”, which was published in 2018 in the journal Management Decision.

The entire introduction spans 611 words and is divided into five paragraphs. In this introduction, the authors accomplish the following:

• In the first paragraph, the authors introduce the broader topic of the literature review, which focuses on innovation and its significance in the context of economic competition. They underscore the importance of this topic, highlighting its relevance for both researchers and policymakers.
• In the second paragraph, the authors narrow down their focus to emphasize the specific role of culture in relation to innovation.
• In the third paragraph, the authors identify research gaps, noting that existing studies are often fragmented and disconnected. They then emphasize the value of conducting a systematic literature review to enhance our understanding of the topic.
• In the fourth paragraph, the authors introduce their specific objectives and explain how their insights can benefit other researchers and business practitioners.
• In the fifth and final paragraph, the authors provide an overview of the paper’s organization and structure.

In summary, this introduction stands as a solid example. While the authors deviate from previewing their key findings (which is a common practice at least in the social sciences), they do effectively cover all the other previously mentioned points.

Example 2: An effective introduction to a literature review section in an academic paper

The second example represents a typical academic paper, encompassing not only a literature review section but also empirical data, a case study, and other elements. We will closely examine the introduction to the literature review section in the paper “The environmentalism of the subalterns: a case study of environmental activism in Eastern Kurdistan/Rojhelat”, which was published in 2021 in the journal Local Environment.

The paper begins with a general introduction and then proceeds to the literature review, designated by the authors as their conceptual framework. Of particular interest is the first paragraph of this conceptual framework, comprising 142 words across five sentences:

“ A peripheral and marginalised nationality within a multinational though-Persian dominated Iranian society, the Kurdish people of Iranian Kurdistan (a region referred by the Kurds as Rojhelat/Eastern Kurdi-stan) have since the early twentieth century been subject to multifaceted and systematic discriminatory and exclusionary state policy in Iran. This condition has left a population of 12–15 million Kurds in Iran suffering from structural inequalities, disenfranchisement and deprivation. Mismanagement of Kurdistan’s natural resources and the degradation of its natural environmental are among examples of this disenfranchisement. As asserted by Julian Agyeman (2005), structural inequalities that sustain the domination of political and economic elites often simultaneously result in environmental degradation, injustice and discrimination against subaltern communities. This study argues that the environmental struggle in Eastern Kurdistan can be asserted as a (sub)element of the Kurdish liberation movement in Iran. Conceptually this research is inspired by and has been conducted through the lens of ‘subalternity’ ” ( Hassaniyan, 2021, p. 931 ).

In this first paragraph, the author is doing the following:

• The author contextualises the research
• The author links the research focus to the international literature on structural inequalities
• The author clearly presents the argument of the research
• The author clarifies how the research is inspired by and uses the concept of ‘subalternity’.

Thus, the author successfully introduces the literature review, from which point onward it dives into the main concept (‘subalternity’) of the research, and reviews the literature on socio-economic justice and environmental degradation.

While introductions to a literature review section aren’t always required to offer the same level of study context detail as demonstrated here, this introduction serves as a commendable model for orienting the reader within the literature review. It effectively underscores the literature review’s significance within the context of the study being conducted.

Examples 3-5: Effective introductions to literature review chapters

The introduction to a literature review chapter can vary in length, depending largely on the overall length of the literature review chapter itself. For example, a master’s thesis typically features a more concise literature review, thus necessitating a shorter introduction. In contrast, a Ph.D. thesis, with its more extensive literature review, often includes a more detailed introduction.

Numerous universities offer online repositories where you can access theses and dissertations from previous years, serving as valuable sources of reference. Many of these repositories, however, may require you to log in through your university account. Nevertheless, a few open-access repositories are accessible to anyone, such as the one by the University of Manchester . It’s important to note though that copyright restrictions apply to these resources, just as they would with published papers.

Master’s thesis literature review introduction

The first example is “Benchmarking Asymmetrical Heating Models of Spider Pulsar Companions” by P. Sun, a master’s thesis completed at the University of Manchester on January 9, 2024. The author, P. Sun, introduces the literature review chapter very briefly but effectively:

PhD thesis literature review chapter introduction

The second example is Deep Learning on Semi-Structured Data and its Applications to Video-Game AI, Woof, W. (Author). 31 Dec 2020, a PhD thesis completed at the University of Manchester . In Chapter 2, the author offers a comprehensive introduction to the topic in four paragraphs, with the final paragraph serving as an overview of the chapter’s structure:

PhD thesis literature review introduction

The last example is the doctoral thesis Metacognitive strategies and beliefs: Child correlates and early experiences Chan, K. Y. M. (Author). 31 Dec 2020 . The author clearly conducted a systematic literature review, commencing the review section with a discussion of the methodology and approach employed in locating and analyzing the selected records.

Having absorbed all of this information, let’s recap the essential steps and offer a succinct guide on how to proceed with creating your literature review introduction:

• Contextualize your review : Begin by clearly identifying the academic context in which your literature review resides and determining the necessary information to include.
• Outline your structure : Develop a structured outline for your literature review, highlighting the essential information you plan to incorporate in your introduction.
• Literature review process : Conduct a rigorous literature review, reviewing and analyzing relevant sources.
• Summarize and abstract : After completing the review, synthesize the findings and abstract key insights, trends, and knowledge gaps from the literature.
• Craft the introduction : Write your literature review introduction with meticulous attention to the seamless integration of your review into the larger context of your work. Ensure that your introduction effectively elucidates your rationale for the chosen review topics and the underlying reasons guiding your selection.

Master Academia

Get new content delivered directly to your inbox.

Subscribe and receive Master Academia's quarterly newsletter.

The best answers to "What are your plans for the future?"

10 tips for engaging your audience in academic writing, related articles.

10 key skills of successful master’s students

How to write effective cover letters for a paper submission

Dealing with failure as a PhD student

Reject decisions: Sample peer review comments and examples

• Harvard Library
• Research Guides
• Harvard Graduate School of Design - Frances Loeb Library

Write and Cite

• Literature Review
• Academic Integrity
• Citing Sources
• Fair Use, Permissions, and Copyright
• Writing Resources
• Grants and Fellowships
• Last Updated: Apr 26, 2024 10:28 AM
• URL: https://guides.library.harvard.edu/gsd/write

Harvard University Digital Accessibility Policy

Academia.edu no longer supports Internet Explorer.

To browse Academia.edu and the wider internet faster and more securely, please take a few seconds to  upgrade your browser .

Enter the email address you signed up with and we'll email you a reset link.

• We're Hiring!
• Help Center

Doing a literature review Aims and Objectives What is a literature review

Related Papers

HUMANUS DISCOURSE

Humanus Discourse

The importance of literature review in academic writing of different categories, levels, and purposes cannot be overemphasized. The literature review establishes both the relevance and justifies why new research is relevant. It is through a literature review that a gap would be established, and which the new research would fix. Once the literature review sits properly in the research work, the objectives/research questions naturally fall into their proper perspective. Invariably, other chapters of the research work would be impacted as well. In most instances, scanning through literature also provides you with the need and justification for your research and may also well leave a hint for further research. Literature review in most instances exposes a researcher to the right methodology to use. The literature review is the nucleus of a research work that might when gotten right spotlights a work and can as well derail a research work when done wrongly. This paper seeks to unveil the practical guides to writing a literature review, from purpose, and components to tips. It follows through the exposition of secondary literature. It exposes the challenges in writing a literature review and at the same time recommended tips that when followed will impact the writing of the literature review.

Ignacio Illan Conde

Andrew Johnson

This chapter describes the process of writing a literature review and what the product should look like

Rebekka Tunombili

Cut Oktaviani

Abdullah Ramdhani , Tatam Chiway , Muhammad Ali Ramdhani

How to Practice Academic Medicine and Publish from Developing Countries?

In scientific writing, whether it is a research paper, thesis, or dissertation, it is important to investigate a problem that has not been tackled before—that is, to fill a gap in the current knowledge. The first question an editor or reviewer asks after seeing a submission is ‘Why did the authors do the work, is the subject original?’

Alfi Rahman

This Study Guide explains why literature reviews are needed, and how they can be conducted and reported. Related Study Guides are: Referencing and bibliographies, Avoiding plagiarism, Writing a dissertation, What is critical reading? What is critical writing? The focus of the Study Guide is the literature review within a dissertation or a thesis, but many of the ideas are transferable to other kinds of writing, such as an extended essay, or a report. After reading your literature review, it should be clear to the reader that you have up-to-date awareness of the relevant work of others, and that the research question you are asking is relevant. However, don't promise too much! Be wary of saying that your research will solve a problem, or that it will change practice. It would be safer and probably more realistic to say that your research will 'address a gap', rather than that it will 'fill a gap'.

A literature review is a critical consideration of the work by authors and researchers who have written on a particular topic. IT involves synthesising these writings so that a 'picture' of the issue under review forms. Therefore, it requires you to use summarising, analytical and evaluative skills. The effectiveness of these will, to a large extent, depend on your ability to link the work of various authors highlighting similarities, differences, strengths and weaknesses. A Literature Review is not a list describing or summarising one piece of literature after another, so avoid beginning each paragraph with the name of the researcher.

yakubu nawati

RELATED PAPERS

Bjørn Einar Bjartnes

Engel Pascalade

Pacing and Clinical Electrophysiology

Isaac Aidonidis

Bidhya Kunwar, Ph.D

Ekonomi, Politika &amp; Finans Araştırmaları Dergisi

Mustafa Bekar

Oecologia Australis

Marina Suzuki

Fabiano Engelmann

SPIE Proceedings

Peter H. Thaller

LUIS ALBERTO HERRERA MONTERO

Journal of Chromatographic Science

MEHMET ŞEKER

International Journal of Digital Earth

Ming-Hsiang Tsou

Journal of Surgical Oncology

Rohan Gupta

Nursing News : Jurnal Ilmiah Mahasiswa Keperawatan

tavip dwi wahyuni

Foot & Ankle Orthopaedics

valeria lopez

Biophysical Journal

Harpreet Singh

European Respiratory Journal

Ricardo del Olmo

Roopa Sachidananda

The Journal of Clinical Psychiatry

gumjee choi

Tri Hesti Utaminingtyas

Molecular Carcinogenesis

Andres J P Klein-Szanto

David Arnulfo Miranda Mendoza

njjfr hggtgrf

IOP conference series

Milorad Jovanovski

Era's Journal of Medical Research

Aparna Misra

Monografía del BID

•   We're Hiring!
•   Help Center
• Find new research papers in:
• Health Sciences
• Earth Sciences
• Cognitive Science
• Mathematics
• Computer Science
• Academia ©2024

A comprehensive examination of load balancing algorithms in cloud environments: a systematic literature review, comparative analysis, taxonomy, open challenges, and future trends

• Published: 24 April 2024

Cite this article

• Farida Siddiqi Prity 1 , 3 &
• Md. Maruf Hossain 2 , 3  

Explore all metrics

Cloud computing is a robust paradigm that empowers users and organizations to procure services tailored to their needs. This model encompasses many offerings, including storage solutions, platforms for seamless deployment, and convenient access to web services. Load balancing, a fundamental pillar in cloud computing, is crucial in distributing requests across multiple servers to optimize resource utilization and reduce response times. However, load balancing presents a common challenge in the cloud environment, as it hampers the ability to maintain optimal application performance while adhering to the stringent requirements of Quality of Service (QoS) measurements and Service Level Agreement (SLA) compliance mandated by cloud providers to enterprises. The equitable workload distribution across servers poses a significant challenge for cloud providers. Hence, an efficient load-balancing technique should optimize resource utilization in Virtual Machines (VMs) to ensure maximum user satisfaction and overall system efficiency. However, existing review papers on load balancing in cloud environments often exhibit limitations, lacking in-depth analyses, graphical representations, and comprehensive evaluations of performance metrics. This review paper aims to fill these gaps by providing a novel taxonomy of load balancing algorithms divided into four categories (types of algorithms, nature of problem, metrics, and simulation tools) and thoroughly examining their objectives, parameters, and operational flows. It evaluates the strengths and weaknesses of these algorithms, considering their nature and type, and employs qualitative QoS parameter-based criteria for effectiveness evaluation. The paper also includes a comparative analysis of simulation tools, visual representations, and experimental results. By offering valuable insights, open issues, recommendations, and future directions, this review paper equips researchers, practitioners, and cloud service providers with the knowledge to make informed decisions in selecting and optimizing load-balancing strategies for diverse cloud environments.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price includes VAT (Russian Federation)

Instant access to the full article PDF.

Rent this article via DeepDyve

Institutional subscriptions

Similar content being viewed by others

Energy efficiency in cloud computing data centers: a survey on software technologies

Efficient Virtual Machine Placement Strategy Based on Enhanced Genetic Approach

A survey of Kubernetes scheduling algorithms

Availability of data and materials.

The datasets generated during the current study are available from the corresponding author on reasonable request.

Luo, Y., Chen, Y., Li, T., Tan, C., Dou, H.: Cloud-SMPC: two-round multilinear maps secure multiparty computation based on LWE assumption. J. Cloud Comput. 13 (1), 22 (2024)

Article   Google Scholar  

Maurya, M., Panigrahi, I., Dash, D., Malla, C.: Intelligent fault diagnostic system for rotating machinery based on IoT with cloud computing and artificial intelligence techniques: a review. Soft. Comput. 28 (1), 477–494 (2024)

Mikram, H., El Kafhali, S., Saadi, Y.: HEPGA: a new effective hybrid algorithm for scientific workflow scheduling in cloud computing environment. Simul. Model. Pract. Theory 130 , 102864 (2024)

Shafiq, D.A., Jhanjhi, N.Z., Abdullah, A.: Load balancing techniques in cloud computing environment: a review. J. King Saud Univ. Comput. Inf. Sci. 34 (7), 3910–3933 (2022)

Google Scholar  

Chen, X., Li, J., Chen, D., Zhou, Y., Tu, Z., Lin, M., Kang, T., Lin, J., Gong, T., Zhu, L., Zhou, J.: CloudBrain-MRS: an intelligent cloud computing platform for in vivo magnetic resonance spectroscopy preprocessing, quantification, and analysis. J. Magn. Reson. 358 , 107601 (2024)

Kumar, A., Chawla, P.: A systematic literature review on load balancing algorithms of virtual machines in a Cloud computing environment. In: Proceedings of the International Conference on Innovative Computing and Communications (ICICC) (2020, March)

Mishra, S.K., Sahoo, B., Parida, P.P.: Load balancing in cloud computing: a big picture. J. King Saud Univ. Comput. Inf. Sci. 32 (2), 149–158 (2020)

Megharaj, G., Mohan, K.G.: A survey on load balancing techniques in cloud computing. IOSR J. Comput. Eng. (IOSR-JCE) 18 (2), 55–61 (2016)

Kumar, B.S., Parthiban, D.L.: An implementation of load balancing policy for virtual machines associated with a data centre. Int. J. Comput. Sci. Eng. Technol. (IJCSET) 5 (03), 253–261 (2014)

Kumar, P., Kumar, R.: Issues and challenges of load balancing techniques in cloud computing: a survey. ACM Comput. Surv. (CSUR) 51 (6), 1–35 (2019)

Lakhwani, K.: ‘An extensive survey on load balancing techniques in cloud computinG. J. Gujarat Res. Soc. 21 (10s), 309–319 (2019)

Afzal, S., Kavitha, G.: Load balancing in cloud computing—a hierarchical taxonomical classification. J. Cloud Comput. 8 (1), 22 (2019)

Kathalkar, P.R., Deorankar, A.V.: A review on different load balancing algorithm in cloud computing. Int. Res. J. Eng. Technol. 5 (2), 1–3 (2018)

Kumar, D.S., Dharma Prakash Raj, E.G.: A literature review on load balancing mechanisms in cloud computing. Int. J. Adv. Res. Comput. Sci. 9 (1), 1 (2018)

Kaur, M., Verma, D.B.: A review on various load balancing algorithms with Merits–Demerits in cloud computing. Int. J. Adv. Eng. Res. Dev. 5 (5), 1 (2018)

Hota, A., Mohapatra, S., Mohanty, S.: Survey of different load balancing approach-based algorithms in cloud computing: a comprehensive review. In: Computational Intelligence in Data Mining: Proceedings of the International Conference on CIDM 2017, pp. 99–110. Springer, Singapore (2019)

Mishra, K., Majhi, S.: A state-of-art on cloud load balancing algorithms. Int. J. Comput. Digit. Syst. 9 (2), 201–220 (2020)

Hamadah, S.: A survey: a comprehensive study of static, dynamic and hybrid load balancing algorithms. Int. J. Comput. Sci. Inf. Technol. Secur. (IJCSITS), ISSN, 2249–9555 (2017)

Sutagatti, S.S., Kulkarni, S.G.: Comparative analysis and evaluation of load balancing algorithms. Int. J. Comput. Appl. 171 (5), 6–11 (2017)

Deepa, T., Cheelu, D.: A comparative study of static and dynamic load balancing algorithms in cloud computing. In: 2017 International Conference on Energy, Communication, Data Analytics and Soft Computing (ICECDS), pp. 3375–3378. IEEE (2017, August)

Archana, M., Shastry, M.: A review paper on various load balancing algorithms in cloud computing. J. Eng. Appl. Sci. 12 (9), 8579–8585 (2017)

Gupta, S., Dixit, A., Dev, H.: A study on various load balancing algorithms for response time reduction in cloud. Int. J. Curr. Eng. Sci. Res. (IJCESR) 4 (10), 1 (2017)

Thakur, A., Goraya, M.S.: A taxonomic survey on load balancing in cloud. J. Netw. Comput. Appl. 98 , 43–57 (2017)

Alam, M., Khan, Z.A.: Issues and challenges of load balancing algorithm in cloud computing environment. Indian J. Sci. Technol. 10 (25), 1–12 (2017)

Joshi, S., Kumari, U.: A comprehensive analysis of existing load balancing algorithms in cloud network. Mody Univ. Int. J. Comput. Eng. Res. 1 (2), 71–75 (2017)

Singh, A.B., Bhat, S., Raju, R., D’Souza, R.: Survey on various load balancing techniques in cloud computing. Adv. Comput. 7 (2), 28–34 (2017)

Milani, A.S., Navimipour, N.J.: Load balancing mechanisms and techniques in the cloud environments: systematic literature review and future trends. J. Netw. Comput. Appl. 71 , 86–98 (2016)

Elngomi, Z.M., Khanfar, K.: A comparative study of load balancing algorithms: a review paper. Int. J. Comput. Sci. Mob. Comput. 5 (6), 448–458 (2016)

Goyal, S., Verma, M.K.: Load balancing techniques in cloud computing environment: a review. Int. J. Adv. Res. Comput. Sci. Softw. Eng. 6 (4), 583–588 (2016)

Gabi, D., Ismail, A.S., Zainal, A.: Systematic review on existing load balancing techniques in cloud computing. Int. J. Comput. Appl. 125 (9), 16–24 (2015)

Karthika, K., Kanakambal, K., Balasubramaniam, R.: Load balancing algorithm review’s in cloud environment. IJERGS 3 (3), 661–667 (2015)

Aslam, S., Shah, M.A.: Load balancing algorithms in cloud computing: a survey of modern techniques. In 2015 National Software Engineering Conference (NSEC), pp. 30–35. IEEE (2015, December)

Kapoor, S.: A survey on dynamic load balancing algorithms in cloud computing. Adv. Comput. Sci. Inf. Technol 2 (7), 87–91 (2015)

Sanghavi, H.S., Patalia, D.T.P.: Load balancing algorithms for the cloud computing environment: a review. J. Inf. Knowl. Res. Comput. Eng. 3 (2), 591–598 (2014)

Kaur, R., Luthra, P.: Load balancing in cloud system using max min and min–min algorithm. Int. J. Comput. Appl. 975 , 8887 (2014)

Shafiq, D.A., Jhanjhi, N.Z., Abdullah, A.: Proposing a load balancing algorithm for the optimization of cloud computing applications. In: 2019 13th International Conference on Mathematics, Actuarial Science, Computer Science and Statistics (MACS), pp. 1–6. IEEE (2019, December)

Shah, N., Farik, M.: Static load balancing algorithms in cloud computing: challenges and solutions. Int. J. Sci. Technol. Res. 4 (10), 365–367 (2015)

Islam, T., Hasan, M.S.: A performance comparison of load balancing algorithms for cloud computing. In: 2017 International Conference on the Frontiers and Advances in Data Science (FADS), pp. 130–135. IEEE (2017, October)

Rathore, J., Keswani, B., Rathore, V.S.: Analysis of load balancing algorithms using cloud analyst. In: Emerging Trends in Expert Applications and Security: Proceedings of ICETEAS 2018, pp. 291–298. Springer, Singapore (2019)

Nazar, T., Javaid, N., Waheed, M., Fatima, A., Bano, H., Ahmed, N.: Modified shortest job first for load balancing in cloud-fog computing. In: Advances on Broadband and Wireless Computing, Communication and Applications: Proceedings of the 13th International Conference on Broadband and Wireless Computing, Communication and Applications (BWCCA-2018), pp. 63–76. Springer, London (2019)

Seth, S., Singh, N.: Dynamic heterogeneous shortest job first (DHSJF): a task scheduling approach for heterogeneous cloud computing systems. Int. J. Inf. Technol. 11 (4), 653–657 (2019)

Mondal, R.K., Nandi, E., Sarddar, D.: Load balancing scheduling with shortest load first. Int. J. Grid Distrib. Comput. 8 (4), 171–178 (2015)

Zakria, M., Javaid, N., Ismail, M., Zubair, M., Asad Zaheer, M., Saeed, F.: Cloud-fog based load balancing using shortest remaining time first optimization. In: Advances on P2P, Parallel, Grid, Cloud and Internet Computing: Proceedings of the 13th International Conference on P2P, Parallel, Grid, Cloud and Internet Computing (3PGCIC-2018), pp. 199–211. Springer, London (2019)

Tailong, V., Dimri, V.: Load balancing in cloud computing using modified optimize response time. Int. J. Adv. Res. Comput. Sci. Softw. Eng. 6 (5), 1 (2016)

Kaurav, N.S., Yadav, P.: A genetic algorithm-based load balancing approach for resource optimization for cloud computing environment. Int. J. Inf. Comput. Sci. 6 (3), 175–184 (2019)

Issawi, S.F., Al Halees, A., Radi, M.: An efficient adaptive load balancing algorithm for cloud computing under Bursty workloads. Eng. Technol. Appl. Sci. Res. 5 (3), 795–800 (2015)

Richhariya, V., Dubey, R., Siddiqui, R.: Hybrid technique for load balancing in cloud computing using modified round robin algorithms. J. Comput. Math. Sci. 6 (12), 688–695 (2015)

Richhariya, V., Dubey, R., Siddiqui, R.: Hybrid approach for load balancing in cloud computing. Orient. J. Comput. Sci. Technol. 8 (3), 241–246 (2015)

Pasha, N., Agarwal, A., Rastogi, R.: Round robin approach for VM load balancing algorithm in cloud computing environment. Int. J. Adv. Res. Comput. Sci. Softw. Eng. 4 (5), 34–39 (2014)

Khatavkar, B., Boopathy, P.: Efficient WMaxMin static algorithm for load balancing in cloud computation. In: 2017 Innovations in Power and Advanced Computing Technologies (i-PACT), pp. 1–6. IEEE (2017, April)

Moly, M.I., Hossain, A., Lecturer, S., Roy, O.: Load balancing approach and algorithm in cloud computing environment. Am. J. Eng. Res. 8 (4), 99–105 (2019)

Mayur, S., Chaudhary, N.: Enhanced weighted round robin load balancing algorithm in cloud computing. Int. J. Innov. Technol. Explor. Eng. 8 (9), 148–151 (2019)

James, J., Verma, B.: Efficient VM load balancing algorithm for a cloud computing environment. Int. J. Comput. Sci. Eng. 4 (9), 1658 (2012)

Manaseer, S., Alzghoul, M., Mohmad, M.: An advanced algorithm for load balancing in cloud computing using MEMA technique. Int. J. Innov. Technol. Explor. Eng 8 (3), 36–41 (2019)

Manikandan, N., Pravin, A.: An efficient improved weighted round Robin load balancing algorithm in cloud computing. Int. J. Eng. Technol. (UAE) 7 (3.1), 110–117 (2018)

Chen, S.L., Chen, Y.Y., Kuo, S.H.: CLB: a novel load balancing architecture and algorithm for cloud services. Comput. Electr. Eng. 58 , 154–160 (2017)

Ali, S.A., Alam, M.: Resource-aware Min–Min (RAMM) algorithm for resource allocation in cloud computing environment. Preprint arXiv:1803.00045 (2018)

Patel, G., Mehta, R., Bhoi, U.: Enhanced load balanced min–min algorithm for static meta task scheduling in cloud computing. Proc. Comput. Sci. 57 , 545–553 (2015)

Shanthan, B.H., Arockiam, L.: Resource based load balanced min–min algorithm (RBLMM) for static meta task scheduling in cloud. In International conference on advances in computer science and technology. Int. J. Eng. Technol. Spec. 1–8 , 1 (2018)

Nayak, P., Vania, J., Robin, R.: Load balancing using modified Throttled algorithm. Int. J. Sci. Res. Dev. 3 (3), 3614–3616 (2015)

Ghosh, S., Banerjee, C.: Priority based modified throttled algorithm in cloud computing. In: 2016 International Conference on Inventive Computation Technologies (ICICT), vol. 3, pp. 1–6. IEEE (2016, August)

Phi, N.X., Tin, C.T., Thu, L.N.K., Hung, T.C.: Proposed load balancing algorithm to reduce response time and processing time on cloud computing. Int. J. Comput. Netw. Commun. 10 (3), 87–98 (2018)

Sachdeva, R., Kakkar, S.: A novel approach in cloud computing for load balancing using composite algorithms. Int. J. 7 (2), 198 (2017)

Subalakshmi, S., Malarvizhi, N.: Enhanced hybrid approach for load balancing algorithms in cloud computing. Int. J. Sci. Res. Comput. Sci. Eng. Inf. Technol. 2 (2), 136–142 (2017)

Rathore, J., Keswani, B., Rathore, V.S.: An efficient load balancing algorithm for cloud environment. J. Invent. Comput. Sci. Commun. Technol. 4 (1), 37–41 (2018)

Aliyu, A.N., Souley, P.B.: Performance analysis of a hybrid approach to enhance load balancing in a heterogeneous cloud environment. Int. J. Adv. Sci. Res. Eng. 5 (7), 246–257 (2019)

Khanchi, M., Tyagi, S.: An efficient algorithm for load balancing in cloud computing. Int. J. Eng. Sci. Res. Technol. 5 (6), 468–475 (2016)

Alamin, M.A., Elbashir, M.K., Osman, A.A.: A load balancing algorithm to enhance the response time in cloud computing. J. Basic Appl. Sci. 2 (2), 473–490 (2017)

Mishra, S., Tondon, R.: A shared approach of dynamic load balancing in cloud computing. Int. J. Sci. Res. Sci. Eng. Technol. (ijsrset. com) 2 (02), 632–638 (2016)

Somani, R., Ojha, J.: A hybrid approach for VM load balancing in cloud using cloudsim. Int. J. Sci. Eng. Technol. Res. (IJSETR) 3 (6), 1734–1739 (2014)

Alankar, B., Sharma, G., Kaur, H., Valverde, R., Chang, V.: Experimental setup for investigating the efficient load balancing algorithms on virtual cloud. Sensors 20 (24), 7342 (2020)

Dam, S., Mandal, G., Dasgupta, K., Dutta, P.: Genetic algorithm and gravitational emulation based hybrid load balancing strategy in cloud computing. In: Proceedings of the 2015 Third International Conference on Computer, Communication, Control and Information Technology (C3IT), pp. 1–7. IEEE (2015, February)

Kaur, S., Sengupta, J.: Load balancing using improved genetic algorithm (IGA) in cloud computing. Int. J. Adv. Res. Comput. Eng. Technol. (IJARCET) 6 (8), 1323–2278 (2017)

Saadat, A., Masehian, E.: Load balancing in cloud computing using genetic algorithm and fuzzy logic. In: 2019 International Conference on Computational Science and Computational Intelligence (CSCI), pp. 1435–1440. IEEE (2019, Dec.)

Kaur, K., Kumar, Y.: Swarm intelligence and its applications towards various computing: a systematic review. In: 2020 International Conference on Intelligent Engineering and Management (ICIEM), pp. 57–62. IEEE (2020, June)

Yadav, A.: Load balancing in cloud computing environment using hybrid approach (ESCEL and PSO) algorithms. Adv. Comput. Sci. Inf. Technol. 2 (8), 10–13 (2015)

Alguliyev, R.M., Imamverdiyev, Y.N., Abdullayeva, F.J.: PSO-based load balancing method in cloud computing. Autom. Control. Comput. Sci. 53 , 45–55 (2019)

Golchi, M.M., Saraeian, S., Heydari, M.: A hybrid of firefly and improved particle swarm optimization algorithms for load balancing in cloud environments: performance evaluation. Comput. Netw. 162 , 106860 (2019)

Pan, K., Chen, J.: Load balancing in cloud computing environment based on an improved particle swarm optimization. In: 2015 6th IEEE International Conference on Software Engineering and Service Science (ICSESS), pp. 595–598. IEEE (2015, Sept.)

Miao, Z., Yong, P., Mei, Y., Quanjun, Y., Xu, X.: A discrete PSO-based static load balancing algorithm for distributed simulations in a cloud environment. Futur. Gener. Comput. Syst. 115 , 497–516 (2021)

Hashem, W., Nashaat, H., Rizk, R.: Honey bee based load balancing in cloud computing. KSII Trans. Internet Inf. Syst. 11 (12), 1 (2017)

George, M.S., Das, K.N., Pushpa, B.R.: Enhanced honeybee inspired load balancing algorithm for cloud environment. In: 2017 International Conference on Communication and Signal Processing (ICCSP), pp. 1649–1653. IEEE (2017, April)

Ehsanimoghadam, P., Effatparvar, M.: Load balancing based on bee colony algorithm with partitioning of public clouds. Int. J. Adv. Comput. Sci. Appl. 9 (4), 1 (2018)

Kiritbhai, P.B., Shah, N.Y.: Optimizing load balancing technique for efficient load balancing. Int. J. Innov. Res. Technol. 4 (6), 39–44 (2017)

Gundu, S.R., Anuradha, T.: Improved hybrid algorithm approach based load balancing technique in cloud computing. Global J. Comput. Sci. Technol. 2019 , 1 (2019)

Kumar, R., Prashar, T.: Performance analysis of load balancing algorithms in cloud computing. Int. J. Comput. Appl. 120 (7), 1 (2015)

Dam, S., Mandal, G., Dasgupta, K., Dutta, P.: An ant colony based load balancing strategy in cloud computing. In: Advanced Computing, Networking and Informatics-Volume 2: Wireless Networks and Security Proceedings of the Second International Conference on Advanced Computing, Networking and Informatics (ICACNI-2014), pp. 403–413. Springer, London (2014)

Selvakumar, A., Gunasekaran, D.G.: A novel approach in load balancing for dynamic cloud environment using ACO. Int. Innov. Res. J. Eng. Technol. 2 (04), 67–70 (2017)

Singh, G.S., Vivek, T.: Implementation of a hybrid load balancing algorithm for cloud computing. Int. J. Adv. Technol. Eng. Sci. 3 (1), 73–81 (2015)

Gupta, A., Garg, R.: Load balancing based task scheduling with ACO in cloud computing. In: 2017 International Conference on Computer and Applications (ICCA), pp. 174–179. IEEE (2017, Sept.)

Ragmani, A., Elomri, A., Abghour, N., Moussaid, K., Rida, M.: An improved hybrid fuzzy-ant colony algorithm applied to load balancing in cloud computing environment. Proc. Comput. Sci. 151 , 519–526 (2019)

Junaid, M., Sohail, A., Ahmed, A., Baz, A., Khan, I.A., Alhakami, H.: A hybrid model for load balancing in cloud using file type formatting. IEEE Access 8 , 118135–118155 (2020)

Kumar, A., Kumar, D., Jarial, S.K.: A review on artificial bee colony algorithms and their applications to data clustering. Cybern. Inf. Technol. 17 (3), 3–28 (2017)

MathSciNet   Google Scholar  

Li, J.Q., Han, Y.Q.: A hybrid multi-objective artificial bee colony algorithm for flexible task scheduling problems in cloud computing system. Clust. Comput. 23 (4), 2483–2499 (2020)

Remesh Babu, K.R., Samuel, P.: Enhanced bee colony algorithm for efficient load balancing and scheduling in cloud. In: Innovations in Bio-Inspired Computing and Applications: Proceedings of the 6th International Conference on Innovations in Bio-Inspired Computing and Applications (IBICA 2015) held in Kochi, India during December 16–18, 2015, pp. 67–78. Springer, London (2016)

Abed-Alguni, B.H., Alawad, N.A.: Distributed Grey Wolf Optimizer for scheduling of workflow applications in cloud environments. Appl. Soft Comput. 102 , 107113 (2021)

Faris, H., Aljarah, I., Al-Betar, M.A., Mirjalili, S.: Grey wolf optimizer: a review of recent variants and applications. Neural Comput. Appl. 30 , 413–435 (2018)

Gohil, B.N., Patel, D.R.: A hybrid GWO-PSO algorithm for load balancing in cloud computing environment. In: 2018 Second International Conference on Green Computing and Internet of Things (ICGCIoT), pp. 185–191. IEEE (2018, August)

Xingjun, L., Zhiwei, S., Hongping, C., Mohammed, B.O.: A new fuzzy-based method for load balancing in the cloud-based Internet of things using a grey wolf optimization algorithm. Int. J. Commun. Syst. 33 (8), e4370 (2020)

Ouhame, S., Hadi, Y.: A hybrid grey wolf optimizer and artificial bee colony algorithm used for improvement in resource allocation system for cloud technology. Int. J. Online Biomed. Eng. 16 (14), 1 (2020)

Ullah, A., Nawi, N.M., Khan, M.H.: BAT algorithm used for load balancing purpose in cloud computing: an overview. Int. J. High Perform. Comput. Netw. 16 (1), 43–54 (2020)

Shaddad, R.Q., Mohammad, A.B., Al-Gailani, S.A., Al-Hetar, A.M.: Optical frequency upconversion technique for transmission of wireless MIMO-type signals over optical fiber. Sci. World J. 2014 , 1 (2014)

Raj, B., Ranjan, P., Rizvi, N., Pranav, P., Paul, S.: Improvised bat algorithm for load balancing-based task scheduling. In: Progress in Intelligent Computing Techniques: Theory, Practice, and Applications: Proceedings of ICACNI 2016, Volume 1, pp. 521–530. Springer, Singapore (2018)

Fahim, Y., Rahhali, H., Hanine, M., Benlahmar, E.H., Labriji, E.H., Hanoune, M., Eddaoui, A.: Load balancing in cloud computing using meta-heuristic algorithm. J. Inf. Process. Syst. 14 (3), 1 (2018)

Mirjalili, S., Lewis, A.: The whale optimization algorithm. Adv. Eng. Softw. 95 , 51–67 (2016)

Kaur, G., Arora, S.: Chaotic whale optimization algorithm. J. Computa. Des. Eng. 5 (3), 275–284 (2018)

Strumberger, I., Bacanin, N., Tuba, M., Tuba, E.: Resource scheduling in cloud computing based on a hybridized whale optimization algorithm. Appl. Sci. 9 (22), 4893 (2019)

Hemasian-Etefagh, F., Safi-Esfahani, F.: Dynamic scheduling applying new population grouping of whales meta-heuristic in cloud computing. J. Supercomput. 75 (10), 6386–6450 (2019)

Chen, X., Cheng, L., Liu, C., Liu, Q., Liu, J., Mao, Y., Murphy, J.: A WOA-based optimization approach for task scheduling in cloud computing systems. IEEE Syst. J. 14 (3), 3117–3128 (2020)

James, J.Q., Li, V.O.: A social spider algorithm for global optimization. Appl. Soft Comput. 30 , 614–627 (2015)

Usurelu, C.C., Nita, M.C., Istrate, R., Pop, F., Tapus, N.: Spider mesh overlay for task load balancing in cloud computing. In: 2015 IEEE International Conference on Intelligent Computer Communication and Processing (ICCP), pp. 433–440. IEEE (2015, September)

Mahato, D.P., Singh, R.S.: Balanced task allocation in the on-demand computing-based transaction processing system using social spider optimization. Concurr. Comput. Pract. Exp. 29 (18), e4214 (2017)

Arul Xavier, V.M., Annadurai, S.: Chaotic social spider algorithm for load balance aware task scheduling in cloud computing. Clust. Comput. 22 (Suppl 1), 287–297 (2019)

Abrol, P., Gupta, S., Singh, S.: QoS aware social spider cloud web algorithm: Analysis of resource placement approach. In: Proceedings of International Conference on Advancements in Computing & Management (ICACM) (2019, October)

Polepally, V., Shahu Chatrapati, K.: Dragonfly optimization and constraint measure-based load balancing in cloud computing. Clust. Comput. 22 (Suppl 1), 1099–1111 (2019)

Branch, S.R., Rey, S.: Providing a load balancing method based on dragonfly optimization algorithm for resource allocation in cloud computing. Int. J. Netw. Distrib. Comput. 6 (1), 35–42 (2018)

Neelima, P., Reddy, A.R.M.: An efficient load balancing system using adaptive dragonfly algorithm in cloud computing. Clust. Comput. 23 , 2891–2899 (2020)

Rani, E., Kaur, H.: Efficient load balancing task scheduling in cloud computing using raven roosting optimization algorithm. Int. J. Adv. Res. Comput. Sci. 8 (5), 1 (2017)

Torabi, S., Safi-Esfahani, F.: Improved raven roosting optimization algorithm (IRRO). Swarm Evol. Comput. 40 , 144–154 (2018)

Torabi, S., Safi-Esfahani, F.: A dynamic task scheduling framework based on chicken swarm and improved raven roosting optimization methods in cloud computing. J. Supercomput. 74 (6), 2581–2626 (2018)

Bhargavi, K., Babu, B.S.: Load balancing scheme for the public cloud using reinforcement learning with raven roosting optimization policy (RROP). In: 2019 4th International Conference on Computational Systems and Information Technology for Sustainable Solution (CSITSS), pp. 1–6. IEEE (2019, December)

Chaturvedi, M., Agrawal, P.D.: Optimal load balancing in cloud computing by efficient utilization of virtual machines. Int. J. Innov. Res. Comput. Commun. Eng. 5 (12), 17705–17713 (2017)

Singh, A.N., Prakash, S.: WAMLB: weighted active monitoring load balancing in cloud computing. In: Big Data Analytics: Proceedings of CSI 2015, pp. 677–685. Springer, Singapore (2018)

Soni, G., Kalra, M.: A novel approach for load balancing in cloud data center. In: 2014 IEEE International Advance Computing Conference (IACC), pp. 807–812. IEEE (2014, February)

Panwar, R., Mallick, B.: Load balancing in cloud computing using dynamic load management algorithm. In: 2015 International Conference on Green Computing and Internet of Things (ICGCIoT), pp. 773–778. IEEE (2015, October)

Kaur, S., Sharma, T.: Efficient load balancing using improved central load balancing technique. In: 2018 2nd International Conference on Inventive Systems and Control (ICISC), pp. 1–5. IEEE (2018, January)

Haidri, R.A., Katti, C.P., Saxena, P.C.: A load balancing strategy for cloud computing environment. In: 2014 International Conference on Signal Propagation and Computer Technology (ICSPCT 2014), pp. 636–641. IEEE (2014, July)

Kumar, M., Sharma, S.C.: Dynamic load balancing algorithm for balancing the workload among virtual machine in cloud computing. Proc. Comput. Sci. 115 , 322–329 (2017)

Kumar, M., Sharma, S.C.: Dynamic load balancing algorithm to minimize the makespan time and utilize the resources effectively in cloud environment. Int. J. Comput. Appl. 42 (1), 108–117 (2020)

Nair, A., Anand, S., Sinha, S.: A performance booster for load balancing in cloud computing with my load balancer technique. Int. J. Recent Technol. Eng. 8 (1), 1 (2019)

Banerjee, S., Adhikari, M., Kar, S., Biswas, U.: Development and analysis of a new cloudlet allocation strategy for QoS improvement in cloud. Arab. J. Sci. Eng. 40 , 1409–1425 (2015)

Article   MathSciNet   Google Scholar  

Patel, P., Prajapati, D., Suthar, K.: An efficient and modified load balancing method for cloud computing. Int. J. Innov. Res. Comput. Commun. Eng. 5 (4), 8198–8205 (2017)

Al-Marhabi, R., Haggag, M., Aboutabl, A.E.: Roulette wheel selection model based on virtual machine weight for load balancing in cloud computing. IOSR J. Comput. Eng. 16 (5), 65–70 (2014)

Rekha, P.M., Dakshayini, M.: Dynamic cost-load aware service broker load balancing in virtualization environment. Proc. Comput. Sci. 132 , 744–751 (2018)

Bhatt, H.H., Bheda, H.A.: Enhance load balancing using Flexible load sharing in cloud computing. In: 2015 1st International Conference on Next Generation Computing Technologies (NGCT), pp. 72–76. IEEE (2015, September)

Semmoud, A., Hakem, M., Benmammar, B., Charr, J.C.: Load balancing in cloud computing environments based on adaptive starvation threshold. Concurr. Comput. Pract. Exp. 32 (11), e5652 (2020)

Kaur, S., Ghumman, M.N.S.: Allocation of heterogenous cloudlets on priority basis in cloud environment. Int. J. 16 (3), 1 (2017)

Kamboj, S., Ghumman, M.N.S.: An implementation of load balancing algorithm in cloud environment. Int. J. 15 (9), 1 (2016)

Kamboj, S., Ghumman, M.N.S.: A novel approach of optimizing performance using K-means clustering in cloud computing. Int. J. 15 (14), 1 (2016)

Domanal, S.G., Reddy, G.R.M.: Optimal load balancing in cloud computing by efficient utilization of virtual machines. In: 2014 6th International Conference on Communication Systems and Networks (COMSNETS), pp. 1–4. IEEE.sachdeva (2014, January)

Khaledian, N., Khamforoosh, K., Akraminejad, R., Abualigah, L., Javaheri, D.: An energy-efficient and deadline-aware workflow scheduling algorithm in the fog and cloud environment. Computing, 106 (1), 109–137 (2024)

Singh, S., Singh, P., Tanwar, S.: Energy aware resource allocation via MS-SLnO in cloud data center. Multimed. Tools Appl. 82 (29), 45541–45563 (2023)

Hima Bindu, G.B., Ramani, K., Shoba Bindu, C.: QOS enhanced energy aware task scheduling models in cloud computing. In: Intelligent Technologies: Concepts, Applications, and Future Directions, Volume 2, pp. 145–164. Springer, Singapore (2023)

Murad, S.A., Azmi, Z.R.M., Muzahid, A.J.M., Bhuiyan, M.K.B., Saib, M., Rahimi, N., Prottasha, N.J., Bairagi, A.K.: SG-PBFS: shortest gap-priority based fair scheduling technique for job scheduling in cloud environment. Futur. Gener. Comput. Syst. 150 , 232–242 (2024)

Ramezani Shahidani, F., Ghasemi, A., Toroghi Haghighat, A., Keshavarzi, A.: Task scheduling in edge-fog-cloud architecture: a multi-objective load balancing approach using reinforcement learning algorithm. Computing 105 (6), 1337–1359 (2023)

Belgacem, A., Mahmoudi, S., Ferrag, M.A.: A machine learning model for improving virtual machine migration in cloud computing. J. Supercomput. 2023 , 1–23 (2023)

Nebagiri, M.H., Hnumanthappa, L.P.: Multi-objective of load balancing in cloud computing using Cuckoo search optimization based simulation annealing. Int. J. Intell. Syst. Appl. Eng. 12 (9s), 466–474 (2024)

Junior, M.Y., Freire, R.Z., Seman, L.O., Stefenon, S.F., Mariani, V.C., dos Santos Coelho, L.: Optimized hybrid ensemble learning approaches applied to very short-term load forecasting. Int. J. Electr. Power Energy Syst. 155 , 109579 (2024)

Behera, I., Sobhanayak, S.: Task scheduling optimization in heterogeneous cloud computing environments: a hybrid GA-GWO approach. J. Parallel Distrib. Comput. 183 , 104766 (2024)

Download references

The authors declare that no funds, grants, or other support were received during the preparation of this manuscript.

Author information

Authors and affiliations.

Department of Information and Communication Engineering, Noakhali Science and Technology University, Noakhali, 3814, Bangladesh

Farida Siddiqi Prity

Department of Information and Communication Engineering, Pabna University of Science and Technology, Pabna, 6600, Bangladesh

Md. Maruf Hossain

Department of Computer Science and Engineering, Shanto-Mariam University of Creative Technology, Dhaka, 1230, Bangladesh

Farida Siddiqi Prity & Md. Maruf Hossain

You can also search for this author in PubMed   Google Scholar

Contributions

Farida Siddiqi Prity: writing original draft, literature surveys, writing—review and editing; Md. Maruf Hossain: study conception and investigation on challenges.

Corresponding author

Correspondence to Farida Siddiqi Prity .

Ethics declarations

Conflict of interest.

The authors have no conflict of interest to disclose.

Consent for publication

Not applicable.

Ethics approval and consent to participate

This article does not contain any studies with human participants and animals performed by any of the authors.

Additional information

Publisher's note.

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Prity, F.S., Hossain, M.M. A comprehensive examination of load balancing algorithms in cloud environments: a systematic literature review, comparative analysis, taxonomy, open challenges, and future trends. Iran J Comput Sci (2024). https://doi.org/10.1007/s42044-024-00183-y

Download citation

Received : 29 January 2024

Accepted : 26 March 2024

Published : 24 April 2024

DOI : https://doi.org/10.1007/s42044-024-00183-y

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

• Cloud computing
• Load balancing
• Find a journal
• Publish with us
• Track your research

SYSTEMATIC REVIEW article

Post-covid-19 headache-ndph phenotype: a systematic review of case reports provisionally accepted.

• 1 Banaras Hindu University, India

The final, formatted version of the article will be published soon.

Background and objectives: Post-acute COVID-19 syndrome or 'long COVID' affects patients even after the recovery from Covid infection in various ways. Persistent headache or New Daily Persistent Headache (NDPH) is one of such symptoms. In this review, we will discuss about the case-reports of post covid-19 headache-NDPH phenotype both after and in the course of COVID-19 infection.Case reports/studies talked about patients having NDPH around the disease either immediately or late post COVID were included. Data was taken from the source and synthesised on a qualitative basis.Results: Literature search showed 3538 articles, out of which 12 were screened as per the eligibility criteria and finally, 4 case reports on NDPH and Covid-19 were chosen for analysis from the database and by human search. All case reports justify the criteria for acceptability in quality for this systematic review.Covid 19 infection is something that is currently an ingenious debated topic in the scientific community. More case studies should be written and published on the same subject so that a large systematic review could be conducted.The review is registered in Prospero with no.

Keywords: COVID - 19, Pain, Headache - Classification, review - systematic, persistent (chronic) pain

Received: 25 Jan 2024; Accepted: 26 Apr 2024.

Copyright: © 2024 Dhiman, Joshi, Singh, Gyanpuri and Kumar. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY) . The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Prof. Deepika Joshi, Banaras Hindu University, Varanasi, India

People also looked at

Click through the PLOS taxonomy to find articles in your field.

For more information about PLOS Subject Areas, click here .

Loading metrics

Open Access

Peer-reviewed

Research Article

Echogenic intracardiac foci detection and location in the second-trimester ultrasound and association with fetal outcomes: A systematic literature review

Roles Formal analysis, Investigation, Validation, Visualization, Writing – original draft, Writing – review & editing

* E-mail: [email protected]

Affiliation National Centre for Population Health and Wellbeing Research, Swansea, United Kingdom

Roles Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Visualization, Writing – original draft, Writing – review & editing

Affiliation Swansea University, Sketty, Swansea, United Kingdom

Roles Data curation, Formal analysis, Writing – review & editing

Affiliation Cardiff University, University Hospital of Wales, Cardiff, United Kingdom

Roles Writing – review & editing

Affiliation Cardiff and Vale UHB: NHS Wales Cardiff and Vale University Health Board, Children’s Heart Unit, Cardiff, United Kingdom

Roles Formal analysis, Investigation, Methodology, Project administration, Visualization, Writing – original draft, Writing – review & editing

• Hope Eleri Jones, 
• Serica Battaglia, 
• Lisa Hurt, 
• Orhan Uzun, 
• Sinead Brophy

• Published: April 22, 2024
• https://doi.org/10.1371/journal.pone.0298365
• Peer Review
• Reader Comments

Echogenic Intracardiac Foci (EIF) are non-structural markers identified during the routine 18–20-week foetal anomaly ultrasound scan yet their clinical significance on future outcomes for the infant is unclear.

To examine the association between EIF and risk of preterm birth, chromosomal abnormalities, and cardiac abnormalities.

A review across four databases to identify English language journal articles of EIF using a cohort study design. All studies were reviewed for quality using the Critical Appraisal Skills Programme (CASP) checklist and data extracted for comparison and analysis.

19 papers from 9 different countries were included. Combining these studies showed 4.6% (95% CI = 4.55–4.65%) of all pregnancies had EIF which was on the left in 86% of cases, on the right in 3% of cases and bilaterally in 10%. There was no evidence that EIF was associated with higher rates of preterm birth. However, it is possible that infants with EIF were more likely to be terminated rather than be born preterm as there was a 2.1% (range 0.3–4.2%) rate of termination or death of the foetus after week 20 among those with EIF. There was no evidence that EIF alone is highly predictive of chromosomal abnormalities. There was evidence that EIF is associated with higher rates of minor cardiac abnormalities (e.g. ventricular septal defect, tricuspid regurgitation or mitral regurgitation)) with 5.1% (224 of 4385) of those with EIF showing cardiac abnormalities (3.08% in retrospective studies and 17.85% in prospective studies). However, the risk of cardiac defects was only higher with right-sided EIF and where the EIF persisted into the third trimester. However, this is a rare event and would be seen in an estimated 4 per 10,000 pregnancies.

EIF alone was not associated with adverse outcomes for the infant. Only persistent EIF on the right side showed evidence of carrying a higher risk of cardiac abnormality and would warrant further follow-up.

Citation: Jones HE, Battaglia S, Hurt L, Uzun O, Brophy S (2024) Echogenic intracardiac foci detection and location in the second-trimester ultrasound and association with fetal outcomes: A systematic literature review. PLoS ONE 19(4): e0298365. https://doi.org/10.1371/journal.pone.0298365

Editor: Mateen A. Khan, Alfaisal University, SAUDI ARABIA

Received: October 26, 2023; Accepted: January 24, 2024; Published: April 22, 2024

Copyright: © 2024 Jones et al. This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: This is a literature review so the relevant data is in each of the papers mentioned in the review that are all open access. The values behind the measures reported and used to build graphs and figures are provided in the supplementary information .

Funding: The author(s) received no specific funding for this work.

Competing interests: The authors have declared that no competing interests exist.

Introduction

Congenital heart disease (CHD) is characterised by defects in the heart as it forms in the growing foetus [ 1 ]. CHD is the most common congenital abnormality in infants today with a diagnosis made 1 in every 100 births [ 2 , 3 ]. CHD is the leading cause of infant mortality [ 3 , 4 ]. Improvements in early detection and diagnosis would greatly improve the support and service provision for families when the infant is born, developing early preventative interventions, and putting in place enhanced monitoring and care for the infant.

A foetal anomaly scan is offered to all pregnant women in the UK between weeks 18-to-20 of pregnancy which includes routine screening for CHD [ 5 , 6 ]. However, it is estimated that only 50% - 75% of cases of serious congenital cardiac abnormalities are detected during this scan [ 5 ]. Potential discrepancies may be due to variations in equipment and facilities available to undertake the appropriate level of screening [ 7 ]. The extensive use and improvements to ultrasound imaging has enabled more detailed detection of fetal structural variations alongside the identification of more subtle non-structural findings, labelled as markers [ 7 – 9 ]. This has led to the identification of ultrasound soft markers (USM) [ 10 ], including Echogenic Intracardiac Foci (EIF), which are often discovered as an incidental finding during prenatal screening [ 11 ].

EIF have been described as small echogenic areas of microcalcification or fibrosis on the papillary muscle of either or both atrioventricular valves of the foetal heart [ 12 ]. EIF are often referred to as echo bright spots or hyper echogenicity of foetal soft tissue [ 13 , 14 ] when visualised on a foetal ultrasound. They are of equal or greater brightness than the surrounding bone [ 15 , 16 ]. The pathological cause of EIF remains ambiguous and it is still unclear what is the significance, if any, in terms of defects in the developing heart of the foetus. Research has suggested that EIF prevalence during this second-trimester scan is estimated to occur in between 0.17% and 20% of pregnancies [ 7 ]. The prevalence varies by race, with the highest incidence found amongst Asian populations [ 17 ].

Previous research has described EIF as often transient, resolving by the third trimester of pregnancy or after delivery [ 18 ], nonpathological or benign in isolation [ 11 ], and therefore has been highlighted that isolated soft markers may be present in 10% of normal foetuses [ 19 ]. However, multiple USM and the presence of specific soft markers, in terms of the specific location and size, may be associated with underlying chromosomal abnormalities (such as an association between the presence of EIF and a later diagnosis of Down’s syndrome) albeit the current evidence is not supportive of this [ 20 ] or adverse infant outcomes [ 21 ]. This suggests that the presence of specific soft markers may be associated with structural abnormalities and developmental conditions [ 22 ].

Given that EIF are small structures within the foetal ventricle chamber, they have been commonly associated with other soft markers [ 19 ]. However, it is unclear whether EIF can be used as a screening tool for cardiac heart diseases as previous research has shown mixed results. Despite the possible concerns surrounding the association between the development of structural and chromosomal abnormalities in the affected foetus, available data is debatable and inconclusive in some publications whilst others clearly showed no significance.

The presence of EIF with additional risk factors such as older maternal age (>35 years) places the mother in a high-risk category [ 22 ] during the pregnancy. Depending on the association with other soft markers this may lead to a referral for an echocardiogram and/or genetic counselling for amniocentesis to investigate possible chromosomal abnormalities. If EIF persists until birth and is present alongside other soft markers, a postnatal echocardiogram would be recommended and a referral to neonatal consultant. However, with increasing maternal age [ 23 ] and improvements in ultrasound detection [ 9 ] this is becoming more common therefore adding to costs of healthcare, potentially with little gain as the prevalence of congenital abnormality has remained constant [ 24 ].

It remains unclear whether EIF encompasses both benign transient structural variations and pathological changes [ 18 , 22 ]. Distinguishing between these two would be significant in terms of determining those to take forward for echocardiography and this is especially important in times of financial strain on the NHS. It is unclear whether location of EIF and number of EIFs are of more significance rather than their presence or absence.

The aim of this literature review is to examine the association between EIF and infant outcomes. Specifically: 1) The association between EIF identified at 18–20 weeks and risk of preterm birth, death, specific cardiac diagnosis (CHD) and chromosomal abnormalities. 2) The association between the number of EIF (single vs multiple), the location of EIF (left, right or bilateral) and the risk of preterm birth, death, cardiac diagnosis, and chromosomal abnormalities.

This review follows the Population-Interest-Comparator-Outcome (PICO) criteria to guide the scope and breadth of the literature review and set the inclusion criteria. The population was defined as the foetus at the 18–20-week ultrasound scan. The interest was where EIF was identified in the scan (as identified by the sonographer) compared to the comparator of those with no EIF. The infant outcomes include preterm delivery, death, structural cardiac abnormality, and chromosomal abnormalities.

Inclusion criteria

Peer-reviewed cohort studies in English, with full-text availability, published between 2013–2023. Studies included prospective and retrospective cohort studies with the assessment of EIF (with or without other markers) recorded by ultrasound at 18–20 weeks gestation and recording through follow-up (e.g., birth and post birth up to 5 years) with one of the outcome variables of interest. Studies which contain follow-up data to birth and infancy following assessment of routine ultrasound screening in a healthcare setting in the second trimester of pregnancy were included. Studies that only followed up EIF pregnancies without a comparison group were included in selected studies. However, if selection bias was present (e.g., only women >35 years) this was recorded in the data quality assessment and incorporated into the interpretation.

Exclusion criteria

Studies were excluded if the full text was not available in English, they examined non-cardiac echogenic focus (e.g. identified within the kidneys, liver, bowel, thyroid, hepatic, and pancreas). Also excluded were those not performed during the second-trimester ultrasound scan or those studies predicting echogenic foci as the outcome rather than the exposure.

Outcome measures

The primary outcome measure is preterm birth (before 37 weeks) or death of the foetus. Secondary outcomes include chromosomal abnormality (genetic testing for aneuploidy, amniocentesis or NIPT (Non-Invasive Prenatal testing) reports) and cardiac abnormality (fetal echocardiology reports and/or postnatal diagnosis).

Literature search

The literature search was carried out in three stages: Stage one was an initial search on Pubmed to identify the index terms which best identify relevant articles. This initial search used the first 10 relevant primary studies and collated the search terms that were used. The second stage took these updated search terms to apply to the; Web of Science online tool which searches the following databases: Web of Science Core Collection, BIOSIS Citation Index, Current Contents Connects, Data Citation Index, Derwent Innovations Index, and MEDLINE (Medical Literature Analysis and Retrieval System Online). This search was repeated on Pubmed and Scopus individually. The final stage reviewed the reference list of the included studies and reviews in the area. Grey literature was also reviewed including the National Congenital Heart Disease Audit (NCHDA). The literature search was carried out in June 2023 and imported onto Covidence software [ 25 ]. The keywords identified for the initial search included: Echogenic intracardiac foci, Chromosomal abnormalities, Prenatal diagnosis, Ultrasonography, Echocardiography, Pregnancy trimester second, Foetal cardiac anomalies OR foetal cardiac abnormalities, Foetal echocardiography, Foetal heart, Trisomy 21 (Down syndrome), Prenatal screening and Pregnancy outcomes. The search terms used to identify relevant papers consisted of four concepts and were combined to form the following search string across all key databases: “echogenic intracardiac foc*” OR “echogenic foc*” OR “intracardiac foc*” OR “cardiac echogenic foc*”.

Study selection

Covidence automatically removes duplicate records [ 25 ]. Initial screening based on the title and abstract was carried out by two independent reviewers based on the inclusion and exclusion criteria. For those publications selected to take forward, a second screening based on the full text was conducted and those selected as relevant were taken forward to data extraction ( Fig 1 ).

• PPT PowerPoint slide
• PNG larger image
• TIFF original image

https://doi.org/10.1371/journal.pone.0298365.g001

Extraction of relevant variables

A data extraction form was designed which included the Critical Appraisal Skills Programme (CASP) quality review [ 26 ] to assess risk of bias. Quality was assessed to include methods of addressing confounding variables, quality of measurement of outcome and exposure and if outcomes by exposure and loss to follow-up. The data includes study identification (number, first author), study demographic information (country, size of study, study design), total number of pregnancies, number with EIF recorded, duration of follow up, recording of outcomes of interest, position (left/right) of EIF and number of EIF (single/multiple). See the supplementary information for details of extracted variables, definitions and how they were recorded ( S1 Table ).

Comparison data

The outcomes for those with no EIF were recorded in the same way as those with EIF reporting the number of preterm births, deaths, congenital abnormalities and cardiac abnormalities.

There were 243 non-duplicate studies that were identified using the search criteria. Of these, 206 were excluded at the title and abstract screening due to studies being published before 2013, not a study examining EIF (e.g., assessing cysts or other soft markers) and non-English studies. 35 full journal articles were reviewed. However, the majority were excluded on the basis that they did not have a cohort design (health economics study or case study or case series), did not have follow-up of those with EIF, or did not have follow up of the outcomes which were considered within this review. After full text review, 19 studies were included ( Fig 2 ). These 19 studies covered 9 different countries with 9 of the studies from China, 2 from Iran and 2 from Pakistan. The smallest study had a follow-up of 7 EIF pregnancies and the largest was 143,067 pregnancies of which 2647 had EIF. 6 studies had prospective follow-up of infants and the remaining 13 had retrospective follow-up using routine medical records.

https://doi.org/10.1371/journal.pone.0298365.g002

The majority of studies were rated as being of moderate quality as there was missing data, or loss to follow-up, especially in the prospective studies. For example, a postpartum follow-up study was performed on women referred for echocardiography and of these 7 had EIF [ 1 ]. This study was rated as high risk of selection bias and so rated moderate. Another study was rated moderate as there was loss to follow-up among some EIF participants [ 27 ]. Other studies were not stratified by EIF characteristics making interpretation difficult and therefore rated low [ 28 ]. Moreover, in some cases the dates of recruitment were not being reported, and it was unclear how many terminations of pregnancies occurred [ 29 ]. Overall, the study quality was rated as moderate and there was a risk of bias such as loss to follow-up or selection bias in various papers.

EIF association with outcomes

This review followed 34,104 women from 19 studies (4 studies did not provide a total number of women screened). Of these, there were 15,600 EIFs or 4.6% (95% CI = 4.55–4.65%) of all pregnancies and 4.5% (range 0.5% to 17.8%) of pregnancies when the EIF proportion of each study was averaged. This highlights that EIF is a relatively common finding on ultrasound scans. In addition, 5 studies followed-up those with EIF only (e.g. a cohort of those with EIF) which identified an additional 1,400 EIFs for follow-up. On average, 26.6% presented with multiple EIFs and the remaining had a single EIF. Taking the averaged levels in each study (6 studies reporting the location of EIF), the EIF was on the left side in 86% of cases, on the right in 3%, and bilaterally in 10%. Therefore, EIF on the right is a rare occurrence that only occurred in 13% of EIFs or 6 per 1000 pregnancies.

Preterm births

Five studies reported the rates of preterm birth where the prevalence was 7.2% (range 2–13%). This rate is comparable to the UK where the preterm rate is 7.8% (23) compared to 13% in North Africa [ 30 ] In two studies that reported preterm rates among non-EIF pregnancies, the range was between 5–20%. Comparing the two papers that reported EIF and non-EIF preterm rates, there was no evidence that EIF is associated with preterm birth with 4.8% (EIF) versus 5.1% (non-EIF) in Wales with the sample size 18,841 EIF (N = 858) [ 31 ], and 13.0% (EIF) versus 20.9% (non-EIF) [ 32 ] with the sample size 9,270 (EIF = 230) in Lebanon. This follow-up in a total of 5 studies (2 with control data) does not provide evidence of higher preterm rates in those with EIF. However, in the study in the UK [ 31 ], the authors had the scans reviewed by a quality assurance panel and of the 858 EIF scans only 615 were assessed by the quality assurance panel as EIF’s. This means that there were 44 preterm births out of 615 with EIF (7.2%) which is in line with population level preterm rates in Wales [ 23 ]. The non EIF was 921 preterm births out of 18,226 pregnancies without EIF (5.1%).

However, it is possible that infants with EIF were more likely to be foetal deaths or termination rather than being born preterm. There was a 2.0% (range 0.3–4.2%) rate of termination or death of the foetus after week 20, among those with EIF. This rate is higher than previously reported [ 33 ] which suggests that less than 0.5% of pregnancies will end in foetal death after 20 weeks. The main cause of death in China and Iran appears to be termination due to suggested chromosomal abnormalities and other soft markers. For example, pregnancies were terminated due to abnormal chromosome numbers (35)(28) and 50% of deaths had chromosomal abnormalities [ 19 ]. Many pregnant women with EIF had invasive foetal testing to screen for chromosomal abnormalities [ 28 ]. The findings presented that the increase in the risk of chromosomal abnormalities in the foetus was related to the pregnant women belonging to high-risk groups, rather than EIF [ 28 ].

In Wales, foetal deaths (0.48% of confirmed EIF pregnancies) were due to stillbirths and induced or spontaneous pregnancy loss. This rate of foetal death is in line with expected rates and comparable to non-EIF rates. In Lebanon, foetal deaths (0.9%) were due to foetal demise but this was at the expected rate and equivalent to non-EIF foetal loss rates. In Pakistan, the deaths were associated with cases of pulmonary artery hypertension and tetralogy of Fallot and were all neonatal deaths ( Fig 3 ). This was a higher-than-expected rate, but the sample size was small.

https://doi.org/10.1371/journal.pone.0298365.g003

Overall, there was no evidence that preterm rates were higher among those with EIF. Terminations were higher in China and Iran, and these were associated with chromosomal abnormalities. The rate of foetal death was not higher in countries like Wales or Lebanon with different health care practices and where invasive foetal testing is not performed when EIF is detected.

Chromosomal abnormalities

Ten studies [ 18 , 19 , 22 , 27 , 31 , 32 , 34 – 37 ] reported chromosomal abnormalities and the rate of abnormalities was 1.98% (range 0–5.7%) among those with EIF. The chromosomal abnormalities identified with EIF were Trisomy 18, 46, 21 XXY, XYY and Turner’s syndrome. Three studies also reported abnormalities among those without EIF and in each of these studies the internal comparison of abnormality rate between EIF and non-EIF suggested no higher rate of chromosomal abnormalities among those with EIF ( Fig 4 ). The sample size of EIF pregnancies were 58 in Ko et al. [ 22 ], 1099 in Wang et al. [ 18 ] and 230 in Mirza et al. [ 32 ].

https://doi.org/10.1371/journal.pone.0298365.g004

Cardiac abnormalities

Cardiac abnormalities were reported in 10 studies [ 1 , 3 , 14 , 15 , 27 , 34 , 37 – 39 ] and the average for all studies was 8.2% (range 1.8% to 39%). When all findings were combined there was a 5.1% rate (224/4385) ( Fig 5 ). The retrospective cohort study findings gave a rate of 3.3% and the prospective studies (with higher rates of missing data and loss to follow-up) was 17.85%. Abnormalities included VSD, tricuspid regurgitation and mitral regurgitation. Two studies reported cardiac abnormalities in non-EIF pregnancies, which ranged from 1.5–3.1%. CHD is thought to affect about <1% of births [ 40 ]. There does appear to be evidence that EIF is associated with higher rates of cardiac abnormality (e.g. 3.3% (95%CI 1.1–5.6) rate of cardiac abnormality). However, it remains that 97% of those detected with EIF will not have a cardiac abnormality. Specific findings from the included studies are available in the supplementary information ( S2 Table ).

https://doi.org/10.1371/journal.pone.0298365.g005

Location of EIF

The location of the EIF was recorded in 6 studies. However, follow-up of proportion with a cardiac abnormality by EIF location was only recorded in three studies [ 14 , 15 , 39 ]. Combining the findings for left EIF compared to right EIF showed 7.9% (6/76) (95% CI: 2.9%-16.4%) of right EIF were associated with cardiac abnormality compared to 3.6% (107/2,992) (95% CI: 2.9%-4.3%) in the left (difference: 4.3% (95%CI: 0.03% to 12.6%)) showing higher rates with right-sided EIF compared to the left [ 14 , 15 , 39 ]. The rate of abnormality in bilateral EIF did not differ from the rate seen in the left EIF. The findings from Chiu [ 39 ] suggested persistent EIF into the third trimester may be associated with higher risk of congenital heart defects such as VSD. Therefore, the follow up of EIF later in pregnancy may be useful to examine if the EIF resolves or persists.

In summary, a EIF in the right ventricle may not resolve as often as that in the left and combining the findings from studies suggested that an EIF in the right is associated with higher rates of cardiac abnormality (7.9% rate if EIF at 20 weeks but this could be higher if persistent beyond 20 weeks). There is ethnic variation in the prevalence of EIF and therefore there is likely to be ethnic variation in the significance of EIF. Only an EIF observed in the third trimester on the right may be associated with cardiac abnormality. However, this would be only 4 per 10,000 pregnancies who would have a right EIF which did not resolve by the third trimester (e.g. 4.5 pregnancies have an EIF, 3% of these are on the right (13.5 per 10,000) and of these 30% persist to third trimester or 4 per 10,000 pregnancies have a persistent EIF on the right). Therefore, EIF in general, is unlikely to be significant as a predictive or screening tool.

Findings from this review highlight that only if the EIF is on the right side and persists until the third trimester, is there a higher chance of cardiac abnormalities (7% risk of cardiac abnormality at 20-week scan), and only in these persistent cases could it be advised that there should be further investigation. This finding that the EIF is not predictive of poor outcomes is significant, especially given the current post COVID-19 strains on health systems worldwide. It must be noted that this data is for isolated markers. There is clear and consistent data that multiple markers are associated with adverse outcomes.

Supportive evidence in terms of the risk of aneuploidy reported that isolated EIF is considered an incidental finding and does not warrant amniocentesis, but that amniocentesis should be undertaken in high-risk cases where other soft markers are identified or there is a history of chromosomal abnormalities in previous pregnancies [ 38 ]. A meta-analysis for the risk of Down’s Syndrome suggests that EIF increases the risk by 5–7 folds [ 41 ]. In contrast, an association between EIF and Trisomy 21 is not always reported [ 42 ]. The Society for Foetal Medicine [ 17 ] recommends that for those with no previous aneuploid screening and have an isolated EIF, there should be genetic counseling to estimate the probability of Trisomy 21 and discussion on options for non-invasive screening.

Findings from this review suggest that an isolated EIF would not warrant further investigation, that multiple foci do not carry a higher risk compared to single foci, and that recommendations to follow-up should be based on other risk factors (e.g., maternal age, family history) rather than the presence of EIF without other soft markers. It was found that there were higher terminations in countries like China where many pregnant women with EIF have invasive tests to screen for abnormalities. This suggests that EIF in these countries may be randomly associated with or a consequence of chromosomal abnormalities rather than being a marker for it or that simply the perceived risk of future abnormalities is enough to lead to a termination. The majority of infants terminated in these studies had Variants of Uncertain Significance (VOUS) and so may have been healthy. In countries where the presence of EIF does not lead to chromosomal testing there was no evidence of higher rates of death among infants with EIF. In low-risk pregnancies with EIF, invasive chromosomal testing may lead to harm, such as an increased abortion rate, and is unlikely to lead to benefits of increased detection of chromosomal abnormalities.

VSD was associated with EIF in some studies [ 1 , 14 , 15 , 27 , 29 , 34 , 38 , 39 ] but this association can also be random and non-causative or consequential. VSD is the most common congenital heart defect in children [ 15 , 27 , 41 , 43 , 44 ]. These often resolve and close spontaneously when the baby is born due to the reversal of vascular resistance at birth. Studies have suggested that overall cardiac function may not be affected by the presence of an isolated EIF when assessed by conventional echocardiography and Tissue Doppler (TD) imaging [ 45 ]. Therefore, in isolation, an EIF may not warrant future follow-up. Previous studies have found an association between the presence of an EIF and the incidence of mitral/tricuspid regurgitation. However, it has been suggested that care needs to be taken when assessing if this is true colour flow generated by atrioventricular valvular regurgitation jets or in fact colour Doppler twinkling artefact (which causes a rapidly changing combination of red and blue complexes behind the EIF which may mimic flow) [ 46 ]. Transient and mild valvular regurgitation can also be seen in fetuses with no cardiovascular anomaly and can be transient and without pathological significance [ 47 ]. Previous research has confirmed rough surfaces, such as that created by microcalcifications or mineralisation in the papillary muscle (which is what EIF is suggested to be) [ 48 , 49 ] is seen to reflect the ultrasound incidence beam and increase pulse duration of received radiofrequency. This may be misinterpreted as movement with the atrioventricular valve when visualised on a foetal echocardiogram [ 46 ]. Finally, the work by Hurt et al. [ 31 ] showed that when the EIF’s were taken to a quality assessment panel, 30% were not confirmed as EIF and were removed from the research analysis. Therefore, the identification of EIF has poor inter-rater reliability.

That there is a link between EIF and cardiac abnormality is supported by Taksande et al. [ 50 ] who recently published a systematic review and meta-analysis and found a prevalence of 4.8% among studies published between 1987–2021. This is comparable to our finding which included 7 of the same studies (but not a meta-analysis) from 2013–2023. The Taksande [ 50 ] analysis did not look at left vs right EIF and did not compare with those without EIF. Our findings suggest, when compared to those without EIF in the same study, only a right sided EIF carries significantly higher risk of cardiac abnormality. A follow-up study by Hurt et al. [ 51 ] published 2023, which followed up the infants with EIF and without EIF for 10 years found no evidence of association of EIF with cardiac admissions or diagnosis of cardiac abnormalities but did find an increased risk of respiratory admissions (Hazard ratio 1.27 (95% CI: 1.04–1.54)). The Hurt study did not look at left vs right EIF but the association with respiratory conditions may support the hypothesis that right sided EIF carries morbidity risk more than left sided EIF.

Strengths and limitations

This work was able to examine outcomes from 15,600 EIFs and reported that EIF at 20 weeks is not significant as a screening tool in pregnancy for infant outcomes at birth. The review covered nine different countries so provides assessment of outcomes for infants of different ethnicities and thus is generalisable. However, the finding that EIF on the right side could carry a 7% risk of cardiac abnormality was based on only two studies and a total of 76 EIFs on the right side. This represents a small sample size which displays high variability in terms of the likelihood of cardiac abnormality (2.9% to 16.9%). An additional study [ 52 ], which was excluded as it was considered that the years of recruitment overlapped with Chiu, 2019 [ 39 ] and so some pregnancies may be replicated in both papers, found a significantly higher prevalence of congenital heart defect in the right ventricle (14.8%, n = 4 cases) compared to left (2.8%, n = 18 cases) (p = 0.0146). In this paper the cases of congenital heart defect were confirmed by postnatal echocardiography and 16.7% (4/24) chose termination of pregnancy upon detection of structural defect. Absence of prospective and contemporary data in the Western world owing to diminished attention to benign EIF may have caused an unintended bias towards ethnic disparity in the current analysis.

This review was not able to examine the risks of persistent right EIFs, which are likely to affect fewer infants but have a higher likelihood of cardiac abnormality. In addition, the variation in studies from different countries means that combining study outcomes to a single score may be prone to error, in terms of concealing the variation which may exist between different ethnic groups.

The studies included in this review used different health care systems and therefore may not be comparable in their definition and identification of adverse infant outcomes. Combining the findings from different studies may also create errors and biases as there is no harmonisation in their definitions of the outcomes. The studies undertaking prospective analysis were prone to missing data and skewed data collection e.g., only those families who returned for assessment were included. Therefore, the prospective studies were rated as weaker and prone to bias compared to the retrospective studies.

The screening process and review was conducted by two independent reviewers performing the extraction in parallel and then comparing decisions to reduce bias. The review benefited from the use of specialist software Covidence to undertake the review [ 25 ]. It allows screening to be more efficient and easily tracked. The date restriction of the last 10 years was justified due to improvements in ultrasound technology in recent years. However, this exclusion criteria may have meant that important previous research was missed.

Recommendations

Persistent EIF in the right side should be investigated using an echocardiogram. There are limited cases and this could help predict cardiovascular abnormality as there is a higher prevalence in this group. However, there is no justification to follow up EIFs on the left and especially those in isolation with no other markers detected. Any recommendation of follow-up would be based on other risk factors such as multiple other soft markers or family history, rather than the presence of an EIF.

This review did not examine the long-term follow-up of infants with EIF and it is possible that persistent EIF could be associated with adult conditions such as VSD or valve regurgitation. Future investigation into failure to thrive, a possible audible murmur, or symptoms such as breathlessness in an infant, may identify longer term adverse outcomes associated with EIF.

Conclusions

In conclusion, we examined the outcomes from 19 studies and present that left sided EIFs are not predictive of poor foetal outcomes, and studies reviewed here suggested these are often transient and resolve with time. Persistent EIF on the right side, which is a rare event in itself, would warrant follow-up. This information is beneficial for pregnant women, families, and clinicians to facilitate the development of appropriate clinical guidelines and care pathways during pregnancy and after birth, including the appropriate use of medical interventions and treatment.

Supporting information

S1 table. extracted variables, definitions and how they were recorded..

https://doi.org/10.1371/journal.pone.0298365.s001

S2 Table. Specific findings from included studies which examine cardiac outcomes.

https://doi.org/10.1371/journal.pone.0298365.s002

https://doi.org/10.1371/journal.pone.0298365.s003

• View Article
• PubMed/NCBI
• Google Scholar
• 2. HQIP. Health Quality Improvement Partnership [Internet]. [cited 2023 Dec 21]. Available from: https://www.hqip.org.uk/
• 33. UC Davies Health. Understanding Second Trimester Loss. Obstetrics and Gynecology. UC Davis Health [Internet]. 4860 Y Street, Suite 2500, Sacramento, CA 95817, Ellison Clinic: 916-734-6900; 2023 [cited 2023 May 8]. Available from: https://health.ucdavis.edu/obgyn/services/family-planning/trimester_loss.html
• 48. Kamaya A, Tuthill, Rubin JM. Twinkling Artifact on Color Doppler Sonography: Dependence on Machine Parameters and Underlying Cause. http://dx.doi.org/102214/ajr18011800215 [Internet]. 2012 Nov 23 [cited 2023 May 6];180(1):215–22. Available from: www.ajronline.org
• 49. Rahmouni A, Bargoin R, Herment A, Bargoin N,Vasile Color Doppler twinkling artifact in hyperechoic regions. https://doi.org/101148/radiology19918633158 [Internet]. 1996 Apr 1 [cited 2023 May 6];199(1):269–71. Available from: https://pubs.rsna.org/doi/10.1148/radiology.199.1.8633158

Help | Advanced Search

Computer Science > Neural and Evolutionary Computing

Title: a survey of decomposition-based evolutionary multi-objective optimization: part ii -- a data science perspective.

Abstract: This paper presents the second part of the two-part survey series on decomposition-based evolutionary multi-objective optimization where we mainly focus on discussing the literature related to multi-objective evolutionary algorithms based on decomposition (MOEA/D). Complementary to the first part, here we employ a series of advanced data mining approaches to provide a comprehensive anatomy of the enormous landscape of MOEA/D research, which is far beyond the capacity of classic manual literature review protocol. In doing so, we construct a heterogeneous knowledge graph that encapsulates more than 5,400 papers, 10,000 authors, 400 venues, and 1,600 institutions for MOEA/D research. We start our analysis with basic descriptive statistics. Then we delve into prominent research/application topics pertaining to MOEA/D with state-of-the-art topic modeling techniques and interrogate their sptial-temporal and bilateral relationships. We also explored the collaboration and citation networks of MOEA/D, uncovering hidden patterns in the growth of literature as well as collaboration between researchers. Our data mining results here, combined with the expert review in Part I, together offer a holistic view of the MOEA/D research, and demonstrate the potential of an exciting new paradigm for conducting scientific surveys from a data science perspective.

Submission history

Access paper:.

• Other Formats

References & Citations

• Google Scholar
• Semantic Scholar

BibTeX formatted citation

Bibliographic and Citation Tools

Code, data and media associated with this article, recommenders and search tools.

• Institution

arXivLabs: experimental projects with community collaborators

arXivLabs is a framework that allows collaborators to develop and share new arXiv features directly on our website.

Both individuals and organizations that work with arXivLabs have embraced and accepted our values of openness, community, excellence, and user data privacy. arXiv is committed to these values and only works with partners that adhere to them.

Have an idea for a project that will add value for arXiv's community? Learn more about arXivLabs .