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• v.106(4); 2018 Oct

A systematic approach to searching: an efficient and complete method to develop literature searches

Associated data.

Creating search strategies for systematic reviews, finding the best balance between sensitivity and specificity, and translating search strategies between databases is challenging. Several methods describe standards for systematic search strategies, but a consistent approach for creating an exhaustive search strategy has not yet been fully described in enough detail to be fully replicable. The authors have established a method that describes step by step the process of developing a systematic search strategy as needed in the systematic review. This method describes how single-line search strategies can be prepared in a text document by typing search syntax (such as field codes, parentheses, and Boolean operators) before copying and pasting search terms (keywords and free-text synonyms) that are found in the thesaurus. To help ensure term completeness, we developed a novel optimization technique that is mainly based on comparing the results retrieved by thesaurus terms with those retrieved by the free-text search words to identify potentially relevant candidate search terms. Macros in Microsoft Word have been developed to convert syntaxes between databases and interfaces almost automatically. This method helps information specialists in developing librarian-mediated searches for systematic reviews as well as medical and health care practitioners who are searching for evidence to answer clinical questions. The described method can be used to create complex and comprehensive search strategies for different databases and interfaces, such as those that are needed when searching for relevant references for systematic reviews, and will assist both information specialists and practitioners when they are searching the biomedical literature.

INTRODUCTION

Librarians and information specialists are often involved in the process of preparing and completing systematic reviews (SRs), where one of their main tasks is to identify relevant references to include in the review [ 1 ]. Although several recommendations for the process of searching have been published [ 2 – 6 ], none describe the development of a systematic search strategy from start to finish.

Traditional methods of SR search strategy development and execution are highly time consuming, reportedly requiring up to 100 hours or more [ 7 , 8 ]. The authors wanted to develop systematic and exhaustive search strategies more efficiently, while preserving the high sensitivity that SR search strategies necessitate. In this article, we describe the method developed at Erasmus University Medical Center (MC) and demonstrate its use through an example search. The efficiency of the search method and outcome of 73 searches that have resulted in published reviews are described in a separate article [ 9 ].

As we aimed to describe the creation of systematic searches in full detail, the method starts at a basic level with the analysis of the research question and the creation of search terms. Readers who are new to SR searching are advised to follow all steps described. More experienced searchers can consider the basic steps to be existing knowledge that will already be part of their normal workflow, although step 4 probably differs from general practice. Experienced searchers will gain the most from reading about the novelties in the method as described in steps 10–13 and comparing the examples given in the supplementary appendix to their own practice.

CREATING A SYSTEMATIC SEARCH STRATEGY

Our methodology for planning and creating a multi-database search strategy consists of the following steps:

• Determine a clear and focused question
• Describe the articles that can answer the question
• Decide which key concepts address the different elements of the question
• Decide which elements should be used for the best results
• Choose an appropriate database and interface to start with
• Document the search process in a text document
• Identify appropriate index terms in the thesaurus of the first database
• Identify synonyms in the thesaurus
• Add variations in search terms
• Use database-appropriate syntax, with parentheses, Boolean operators, and field codes
• Optimize the search
• Evaluate the initial results
• Check for errors
• Translate to other databases
• Test and reiterate

Each step in the process is reflected by an example search described in the supplementary appendix .

1. Determine a clear and focused question

A systematic search can best be applied to a well-defined and precise research or clinical question. Questions that are too broad or too vague cannot be answered easily in a systematic way and will generally result in an overwhelming number of search results. On the other hand, a question that is too specific will result into too few or even zero search results. Various papers describe this process in more detail [ 10 – 12 ].

2. Describe the articles that can answer the question

Although not all clinical or research questions can be answered in the literature, the next step is to presume that the answer can indeed be found in published studies. A good starting point for a search is hypothesizing what the research that can answer the question would look like. These hypothetical (when possible, combined with known) articles can be used as guidance for constructing the search strategy.

3. Decide which key concepts address the different elements of the question

Key concepts are the topics or components that the desired articles should address, such as diseases or conditions, actions, substances, settings, domains (e.g., therapy, diagnosis, etiology), or study types. Key concepts from the research question can be grouped to create elements in the search strategy.

Elements in a search strategy do not necessarily follow the patient, intervention, comparison, outcome (PICO) structure or any other related structure. Using the PICO or another similar framework as guidance can be helpful to consider, especially in the inclusion and exclusion review stage of the SR, but this is not necessary for good search strategy development [ 13 – 15 ]. Sometimes concepts from different parts of the PICO structure can be grouped together into one search element, such as when the desired outcome is frequently described in a certain study type.

4. Decide which elements should be used for the best results

Not all elements of a research question should necessarily be used in the search strategy. Some elements are less important than others or may unnecessarily complicate or restrict a search strategy. Adding an element to a search strategy increases the chance of missing relevant references. Therefore, the number of elements in a search strategy should remain as low as possible to optimize recall.

Using the schema in Figure 1 , elements can be ordered by their specificity and importance to determine the best search approach. Whether an element is more specific or more general can be measured objectively by the number of hits retrieved in a database when searching for a key term representing that element. Depending on the research question, certain elements are more important than others. If articles (hypothetically or known) exist that can answer the question but lack a certain element in their titles, abstracts, or keywords, that element is unimportant to the question. An element can also be unimportant because of expected bias or an overlap with another element.

Schema for determining the optimal order of elements

Bias in elements

The choice of elements in a search strategy can introduce bias through use of overly specific terminology or terms often associated with positive outcomes. For the question “does prolonged breastfeeding improve intelligence outcomes in children?,” searching specifically for the element of duration will introduce bias, as articles that find a positive effect of prolonged breastfeeding will be much more likely to mention time factors in their titles or abstracts.

Overlapping elements

Elements in a question sometimes overlap in their meaning. Sometimes certain therapies are interventions for one specific disease. The Lichtenstein technique, for example, is a repair method for inguinal hernias. There is no need to include an element of “inguinal hernias” to a search for the effectiveness of the Lichtenstein therapy. Likewise, sometimes certain diseases are only found in certain populations. Adding such an overlapping element could lead to missing relevant references.

The elements to use in a search strategy can be found in the plot of elements in Figure 1 , by following the top row from left to right. For this method, we recommend starting with the most important and specific elements. Then, continue with more general and important elements until the number of results is acceptable for screening. Determining how many results are acceptable for screening is often a matter of negotiation with the SR team.

5. Choose an appropriate database and interface to start with

Important factors for choosing databases to use are the coverage and the presence of a thesaurus. For medically oriented searches, the coverage and recall of Embase, which includes the MEDLINE database, are superior to those of MEDLINE [ 16 ]. Each of these two databases has its own thesaurus with its own unique definitions and structure. Because of the complexity of the Embase thesaurus, Emtree, which contains much more specific thesaurus terms than the MEDLINE Medical Subject Headings (MeSH) thesaurus, translation from Emtree to MeSH is easier than the other way around. Therefore, we recommend starting in Embase.

MEDLINE and Embase are available through many different vendors and interfaces. The choice of an interface and primary database is often determined by the searcher’s accessibility. For our method, an interface that allows searching with proximity operators is desirable, and full functionality of the thesaurus, including explosion of narrower terms, is crucial. We recommend developing a personal workflow that always starts with one specific database and interface.

6. Document the search process in a text document

We advise designing and creating the complete search strategies in a log document, instead of directly in the database itself, to register the steps taken and to make searches accountable and reproducible. The developed search strategies can be copied and pasted into the desired databases from the log document. This way, the searcher is in control of the whole process. Any change to the search strategy should be done in the log document, assuring that the search strategy in the log is always the most recent.

7. Identify appropriate index terms in the thesaurus of the first database

Searches should start by identifying appropriate thesaurus terms for the desired elements. The thesaurus of the database is searched for matching index terms for each key concept. We advise restricting the initial terms to the most important and most relevant terms. Later in the process, more general terms can be added in the optimization process, in which the effect on the number of hits, and thus the desirability of adding these terms, can be evaluated more easily.

Several factors can complicate the identification of thesaurus terms. Sometimes, one thesaurus term is found that exactly describes a specific element. In contrast, especially in more general elements, multiple thesaurus terms can be found to describe one element. If no relevant thesaurus terms have been found for an element, free-text terms can be used, and possible thesaurus terms found in the resulting references can be added later (step 11).

Sometimes, no distinct thesaurus term is available for a specific key concept that describes the concept in enough detail. In Emtree, one thesaurus term often combines two or more elements. The easiest solution for combining these terms for a sensitive search is to use such a thesaurus term in all elements where it is relevant. Examples are given in the supplementary appendix .

8. Identify synonyms in the thesaurus

Most thesauri offer a list of synonyms on their term details page (named Synonyms in Emtree and Entry Terms in MeSH). To create a sensitive search strategy for SRs, these terms need to be searched as free-text keywords in the title and abstract fields, in addition to searching their associated thesaurus terms.

The Emtree thesaurus contains more synonyms (300,000) than MeSH does (220,000) [ 17 ]. The difference in number of terms is even higher considering that many synonyms in MeSH are permuted terms (i.e., inversions of phrases using commas).

Thesaurus terms are ordered in a tree structure. When searching for a more general thesaurus term, the more specific (narrower) terms in the branches below that term will also be searched (this is frequently referred to as “exploding” a thesaurus term). However, to perform a sensitive search, all relevant variations of the narrower terms must be searched as free-text keywords in the title or abstract, in addition to relying on the exploded thesaurus term. Thus, all articles that describe a certain narrower topic in their titles and abstracts will already be retrieved before MeSH terms are added.

9. Add variations in search terms (e.g., truncation, spelling differences, abbreviations, opposites)

Truncation allows a searcher to search for words beginning with the same word stem. A search for therap* will, thus, retrieve therapy, therapies, therapeutic, and all other words starting with “therap.” Do not truncate a word stem that is too short. Also, limitations of interfaces should be taken into account, especially in PubMed, where the number of search term variations that can be found by truncation is limited to 600.

Databases contain references to articles using both standard British and American English spellings. Both need to be searched as free-text terms in the title and abstract. Alternatively, many interfaces offer a certain code to replace zero or one characters, allowing a search for “pediatric” or “paediatric” as “p?ediatric.” Table 1 provides a detailed description of the syntax for different interfaces.

Field codes in five most used interfaces for biomedical literature searching

Searching for abbreviations can identify extra, relevant references and retrieve more irrelevant ones. The search can be more focused by combining the abbreviation with an important word that is relevant to its meaning or by using the Boolean “NOT” to exclude frequently observed, clearly irrelevant results. We advise that searchers do not exclude all possible irrelevant meanings, as it is very time consuming to identify all the variations, it will result in unnecessarily complicated search strategies, and it may lead to erroneously narrowing the search and, thereby, reduce recall.

Searching partial abbreviations can be useful for retrieving relevant references. For example, it is very likely that an article would mention osteoarthritis (OA) early in the abstract, replacing all further occurrences of osteoarthritis with OA . Therefore, it may not contain the phrase “hip osteoarthritis” but only “hip oa.”

It is also important to search for the opposites of search terms to avoid bias. When searching for “disease recurrence,” articles about “disease free” may be relevant as well. When the desired outcome is survival , articles about mortality may be relevant.

10. Use database-appropriate syntax, with parentheses, Boolean operators, and field codes

Different interfaces require different syntaxes, the special set of rules and symbols unique to each database that define how a correctly constructed search operates. Common syntax components include the use of parentheses and Boolean operators such as “AND,” “OR,” and “NOT,” which are available in all major interfaces. An overview of different syntaxes for four major interfaces for bibliographic medical databases (PubMed, Ovid, EBSCOhost, Embase.com, and ProQuest) is shown in Table 1 .

Creating the appropriate syntax for each database, in combination with the selected terms as described in steps 7–9, can be challenging. Following the method outlined below simplifies the process:

• Create single-line queries in a text document (not combining multiple record sets), which allows immediate checking of the relevance of retrieved references and efficient optimization.
• Type the syntax (Boolean operators, parentheses, and field codes) before adding terms, which reduces the chance that errors are made in the syntax, especially in the number of parentheses.
• Use predefined proximity structures including parentheses, such as (() ADJ3 ()) in Ovid, that can be reused in the query when necessary.
• Use thesaurus terms separately from free-text terms of each element. Start an element with all thesaurus terms (using “OR”) and follow with the free-text terms. This allows the unique optimization methods as described in step 11.
• When adding terms to an existing search strategy, pay close attention to the position of the cursor. Make sure to place it appropriately either in the thesaurus terms section, in the title/abstract section, or as an addition (broadening) to an existing proximity search.

The supplementary appendix explains the method of building a query in more detail, step by step for different interfaces: PubMed, Ovid, EBSCOhost, Embase.com, and ProQuest. This method results in a basic search strategy designed to retrieve some relevant references upon which a more thorough search strategy can be built with optimization such as described in step 11.

11. Optimize the search

The most important question when performing a systematic search is whether all (or most) potentially relevant articles have been retrieved by the search strategy. This is also the most difficult question to answer, since it is unknown which and how many articles are relevant. It is, therefore, wise first to broaden the initial search strategy, making the search more sensitive, and then check if new relevant articles are found by comparing the set results (i.e., search for Strategy #2 NOT Strategy #1 to see the unique results).

A search strategy should be tested for completeness. Therefore, it is necessary to identify extra, possibly relevant search terms and add them to the test search in an OR relationship with the already used search terms. A good place to start, and a well-known strategy, is scanning the top retrieved articles when sorted by relevance, looking for additional relevant synonyms that could be added to the search strategy.

We have developed a unique optimization method that has not been described before in the literature. This method often adds valuable extra terms to our search strategy and, therefore, extra, relevant references to our search results. Extra synonyms can be found in articles that have been assigned a certain set of thesaurus terms but that lack synonyms in the title and/or abstract that are already present in the current search strategy. Searching for thesaurus terms NOT free-text terms will help identify missed free-text terms in the title or abstract. Searching for free-text terms NOT thesaurus terms will help identify missed thesaurus terms. If this is done repeatedly for each element, leaving the rest of the query unchanged, this method will help add numerous relevant terms to the query. These steps are explained in detail for five different search platforms in the supplementary appendix .

12. Evaluate the initial results

The results should now contain relevant references. If the interface allows relevance ranking, use that in the evaluation. If you know some relevant references that should be included in the research, search for those references specifically; for example, combine a specific (first) author name with a page number and the publication year. Check whether those references are retrieved by the search. If the known relevant references are not retrieved by the search, adapt the search so that they are. If it is unclear which element should be adapted to retrieve a certain article, combine that article with each element separately.

Different outcomes are desired for different types of research questions. For instance, in the case of clinical question answering, the researcher will not be satisfied with many references that contain a lot of irrelevant references. A clinical search should be rather specific and is allowed to miss a relevant reference. In the case of an SR, the researchers do not want to miss any relevant reference and are willing to handle many irrelevant references to do so. The search for references to include in an SR should be very sensitive: no included reference should be missed. A search that is too specific or too sensitive for the intended goal can be adapted to become more sensitive or specific. Steps to increase sensitivity or specificity of a search strategy can be found in the supplementary appendix .

13. Check for errors

Errors might not be easily detected. Sometimes clues can be found in the number of results, either when the number of results is much higher or lower than expected or when many retrieved references are not relevant. However, the number expected is often unknown, and very sensitive search strategies will always retrieve many irrelevant articles. Each query should, therefore, be checked for errors.

One of the most frequently occurring errors is missing the Boolean operator “OR.” When no “OR” is added between two search terms, many interfaces automatically add an “AND,” which unintentionally reduces the number of results and likely misses relevant references. One good strategy to identify missing “OR”s is to go to the web page containing the full search strategy, as translated by the database, and using Ctrl-F search for “AND.” Check whether the occurrences of the “AND” operator are deliberate.

Ideally, search strategies should be checked by other information specialists [ 18 ]. The Peer Review of Electronic Search Strategies (PRESS) checklist offers good guidance for this process [ 4 ]. Apart from the syntax (especially Boolean operators and field codes) of the search strategy, it is wise to have the search terms checked by the clinician or researcher familiar with the topic. At Erasmus MC, researchers and clinicians are involved during the complete process of structuring and optimizing the search strategy. Each word is added after the combined decision of the searcher and the researcher, with the possibility of directly comparing results with and without the new term.

14. Translate to other databases

To retrieve as many relevant references as possible, one has to search multiple databases. Translation of complex and exhaustive queries between different databases can be very time consuming and cumbersome. The single-line search strategy approach detailed above allows quick translations using the find and replace method in Microsoft Word (<Ctrl-H>).

At Erasmus MC, macros based on the find-and-replace method in Microsoft Word have been developed for easy and fast translation between the most used databases for biomedical and health sciences questions. The schema that is followed for the translation between databases is shown in Figure 2 . Most databases simply follow the structure set by the Embase.com search strategy. The translation from Emtree terms to MeSH terms for MEDLINE in Ovid often identifies new terms that need to be added to the Embase.com search strategy before the translation to other databases.

Schematic representation of translation between databases used at Erasmus University Medical Center

Dotted lines represent databases that are used in less than 80% of the searches.

Using five different macros, a thoroughly optimized query in Embase.com can be relatively quickly translated into eight major databases. Basic search strategies will be created to use in many, mostly smaller, databases, because such niche databases often do not have extensive thesauri or advanced syntax options. Also, there is not much need to use extensive syntax because the number of hits and, therefore, the amount of noise in these databases is generally low. In MEDLINE (Ovid), PsycINFO (Ovid), and CINAHL (EBSCOhost), the thesaurus terms must be adapted manually, as each database has its own custom thesaurus. These macros and instructions for their installation, use, and adaptation are available at bit.ly/databasemacros.

15. Test and reiterate

Ideally, exhaustive search strategies should retrieve all references that are covered in a specific database. For SR search strategies, checking searches for their recall is advised. This can be done after included references have been determined by the authors of the systematic review. If additional papers have been identified through other non-database methods (i.e., checking references in included studies), results that were not identified by the database searches should be examined. If these results were available in the databases but not located by the search strategy, the search strategy should be adapted to try to retrieve these results, as they may contain terms that were omitted in the original search strategies. This may enable the identification of additional relevant results.

A methodology for creating exhaustive search strategies has been created that describes all steps of the search process, starting with a question and resulting in thorough search strategies in multiple databases. Many of the steps described are not new, but together, they form a strong method creating high-quality, robust searches in a relatively short time frame.

Our methodology is intended to create thoroughness for literature searches. The optimization method, as described in step 11, will identify missed synonyms or thesaurus terms, unlike any other method that largely depends on predetermined keywords and synonyms. Using this method results in a much quicker search process, compared to traditional methods, especially because of the easier translation between databases and interfaces (step 13). The method is not a guarantee for speed, since speed depends on many factors, including experience. However, by following the steps and using the tools as described above, searchers can gain confidence first and increase speed through practice.

What is new?

This method encourages searchers to start their search development process using empty syntax first and later adding the thesaurus terms and free-text synonyms. We feel this helps the searcher to focus on the search terms, instead of on the structure of the search query. The optimization method in which new terms are found in the already retrieved articles is used in some other institutes as well but has to our knowledge not been described in the literature. The macros to translate search strategies between interfaces are unique in this method.

What is different compared to common practice?

Traditionally, librarians and information specialists have focused on creating complex, multi-line (also called line-by-line) search strategies, consisting of multiple record sets, and this method is frequently advised in the literature and handbooks [ 2 , 19 – 21 ]. Our method, instead, uses single-line searches, which is critical to its success. Single-line search strategies can be easily adapted by adding or dropping a term without having to recode numbers of record sets, which would be necessary in multi-line searches. They can easily be saved in a text document and repeated by copying and pasting for search updates. Single-line search strategies also allow easy translation to other syntaxes using find-and-replace technology to update field codes and other syntax elements or using macros (step 13).

When constructing a search strategy, the searcher might experience that certain parentheses in the syntax are unnecessary, such as parentheses around all search terms in the title/abstract portion, if there is only one such term, there are double parentheses in the proximity statement, or one of the word groups exists for only one word. One might be tempted to omit those parentheses for ease of reading and management. However, during the optimization process, the searcher is likely to find extra synonyms that might consist of one word. To add those terms to the first query (with reduced parentheses) requires adding extra parentheses (meticulously placing and counting them), whereas, in the latter search, it only requires proper placement of those terms.

Many search methods highly depend on the PICO framework. Research states that often PICO or PICOS is not suitable for every question [ 22 , 23 ]. There are other acronyms than PICO—such as sample, phenomenon of interest, design, evaluation, research type (SPIDER) [ 24 ]—but each is just a variant. In our method, the most important and specific elements of a question are being analyzed for building the best search strategy.

Though it is generally recommended that searchers search both MEDLINE and Embase, most use MEDLINE as the starting point. It is considered the gold standard for biomedical searching, partially due to historical reasons, since it was the first of its kind, and more so now that it is freely available via the PubMed interface. Our method can be used with any database as a starting point, but we use Embase instead of MEDLINE or another database for a number of reasons. First, Embase provides both unique content and the complete content of MEDLINE. Therefore, searching Embase will be, by definition, more complete than searching MEDLINE only. Second, the number of terms in Emtree (the Embase thesaurus) is three times as high as that of MeSH (the MEDLINE thesaurus). It is easier to find MeSH terms after all relevant Emtree terms have been identified than to start with MeSH and translate to Emtree.

At Erasmus MC, the researchers sit next to the information specialist during most of the search strategy design process. This way, the researchers can deliver immediate feedback on the relevance of proposed search terms and retrieved references. The search team then combines knowledge about databases with knowledge about the research topic, which is an important condition to create the highest quality searches.

Limitations of the method

One disadvantage of single-line searches compared to multi-line search strategies is that errors are harder to recognize. However, with the methods for optimization as described (step 11), errors are recognized easily because missed synonyms and spelling errors will be identified during the process. Also problematic is that more parentheses are needed, making it more difficult for the searcher and others to assess the logic of the search strategy. However, as parentheses and field codes are typed before the search terms are added (step 10), errors in parentheses can be prevented.

Our methodology works best if used in an interface that allows proximity searching. It is recommended that searchers with access to an interface with proximity searching capabilities select one of those as the initial database to develop and optimize the search strategy. Because the PubMed interface does not allow proximity searches, phrases or Boolean “AND” combinations are required. Phrase searching complicates the process and is more specific, with the higher risk of missing relevant articles, and using Boolean “AND” combinations increases sensitivity but at an often high loss of specificity. Due to some searchers’ lack of access to expensive databases or interfaces, the freely available PubMed interface may be necessary to use, though it should never be the sole database used for an SR [ 2 , 16 , 25 ]. A limitation of our method is that it works best with subscription-based and licensed resources.

Another limitation is the customization of the macros to a specific institution’s resources. The macros for the translation between different database interfaces only work between the interfaces as described. To mitigate this, we recommend using the find-and-replace functionality of text editors like Microsoft Word to ease the translation of syntaxes between other databases. Depending on one’s institutional resources, custom macros can be developed using similar methods.

Results of the method

Whether this method results in exhaustive searches where no important article is missed is difficult to determine, because the number of relevant articles is unknown for any topic. A comparison of several parameters of 73 published reviews that were based on a search developed with this method to 258 reviews that acknowledged information specialists from other Dutch academic hospitals shows that the performance of the searches following our method is comparable to those performed in other institutes but that the time needed to develop the search strategies was much shorter than the time reported for the other reviews [ 9 ].

CONCLUSIONS

With the described method, searchers can gain confidence in their search strategies by finding many relevant words and creating exhaustive search strategies quickly. The approach can be used when performing SR searches or for other purposes such as answering clinical questions, with different expectations of the search’s precision and recall. This method, with practice, provides a stepwise approach that facilitates the search strategy development process from question clarification to final iteration and beyond.

SUPPLEMENTAL FILE

Acknowledgments.

We highly appreciate the work that was done by our former colleague Louis Volkers, who in his twenty years as an information specialist in Erasmus MC laid the basis for our method. We thank Professor Oscar Franco for reviewing earlier drafts of this article.

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Methodology

Research Methods | Definitions, Types, Examples

Research methods are specific procedures for collecting and analyzing data. Developing your research methods is an integral part of your research design . When planning your methods, there are two key decisions you will make.

First, decide how you will collect data . Your methods depend on what type of data you need to answer your research question :

• Qualitative vs. quantitative : Will your data take the form of words or numbers?
• Primary vs. secondary : Will you collect original data yourself, or will you use data that has already been collected by someone else?
• Descriptive vs. experimental : Will you take measurements of something as it is, or will you perform an experiment?

Second, decide how you will analyze the data .

• For quantitative data, you can use statistical analysis methods to test relationships between variables.
• For qualitative data, you can use methods such as thematic analysis to interpret patterns and meanings in the data.

Table of contents

Methods for collecting data, examples of data collection methods, methods for analyzing data, examples of data analysis methods, other interesting articles, frequently asked questions about research methods.

Data is the information that you collect for the purposes of answering your research question . The type of data you need depends on the aims of your research.

Qualitative vs. quantitative data

Your choice of qualitative or quantitative data collection depends on the type of knowledge you want to develop.

For questions about ideas, experiences and meanings, or to study something that can’t be described numerically, collect qualitative data .

If you want to develop a more mechanistic understanding of a topic, or your research involves hypothesis testing , collect quantitative data .

You can also take a mixed methods approach , where you use both qualitative and quantitative research methods.

Primary vs. secondary research

Primary research is any original data that you collect yourself for the purposes of answering your research question (e.g. through surveys , observations and experiments ). Secondary research is data that has already been collected by other researchers (e.g. in a government census or previous scientific studies).

If you are exploring a novel research question, you’ll probably need to collect primary data . But if you want to synthesize existing knowledge, analyze historical trends, or identify patterns on a large scale, secondary data might be a better choice.

Descriptive vs. experimental data

In descriptive research , you collect data about your study subject without intervening. The validity of your research will depend on your sampling method .

In experimental research , you systematically intervene in a process and measure the outcome. The validity of your research will depend on your experimental design .

To conduct an experiment, you need to be able to vary your independent variable , precisely measure your dependent variable, and control for confounding variables . If it’s practically and ethically possible, this method is the best choice for answering questions about cause and effect.

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Your data analysis methods will depend on the type of data you collect and how you prepare it for analysis.

Data can often be analyzed both quantitatively and qualitatively. For example, survey responses could be analyzed qualitatively by studying the meanings of responses or quantitatively by studying the frequencies of responses.

Qualitative analysis methods

Qualitative analysis is used to understand words, ideas, and experiences. You can use it to interpret data that was collected:

• From open-ended surveys and interviews , literature reviews , case studies , ethnographies , and other sources that use text rather than numbers.
• Using non-probability sampling methods .

Qualitative analysis tends to be quite flexible and relies on the researcher’s judgement, so you have to reflect carefully on your choices and assumptions and be careful to avoid research bias .

Quantitative analysis methods

Quantitative analysis uses numbers and statistics to understand frequencies, averages and correlations (in descriptive studies) or cause-and-effect relationships (in experiments).

You can use quantitative analysis to interpret data that was collected either:

• During an experiment .
• Using probability sampling methods .

Because the data is collected and analyzed in a statistically valid way, the results of quantitative analysis can be easily standardized and shared among researchers.

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Research bias

• Hawthorne effect
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Quantitative research deals with numbers and statistics, while qualitative research deals with words and meanings.

Quantitative methods allow you to systematically measure variables and test hypotheses . Qualitative methods allow you to explore concepts and experiences in more detail.

In mixed methods research , you use both qualitative and quantitative data collection and analysis methods to answer your research question .

A sample is a subset of individuals from a larger population . Sampling means selecting the group that you will actually collect data from in your research. For example, if you are researching the opinions of students in your university, you could survey a sample of 100 students.

In statistics, sampling allows you to test a hypothesis about the characteristics of a population.

The research methods you use depend on the type of data you need to answer your research question .

• If you want to measure something or test a hypothesis , use quantitative methods . If you want to explore ideas, thoughts and meanings, use qualitative methods .
• If you want to analyze a large amount of readily-available data, use secondary data. If you want data specific to your purposes with control over how it is generated, collect primary data.
• If you want to establish cause-and-effect relationships between variables , use experimental methods. If you want to understand the characteristics of a research subject, use descriptive methods.

Methodology refers to the overarching strategy and rationale of your research project . It involves studying the methods used in your field and the theories or principles behind them, in order to develop an approach that matches your objectives.

Methods are the specific tools and procedures you use to collect and analyze data (for example, experiments, surveys , and statistical tests ).

In shorter scientific papers, where the aim is to report the findings of a specific study, you might simply describe what you did in a methods section .

In a longer or more complex research project, such as a thesis or dissertation , you will probably include a methodology section , where you explain your approach to answering the research questions and cite relevant sources to support your choice of methods.

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Transformations That Work

• Michael Mankins
• Patrick Litre

More than a third of large organizations have some type of transformation program underway at any given time, and many launch one major change initiative after another. Though they kick off with a lot of fanfare, most of these efforts fail to deliver. Only 12% produce lasting results, and that figure hasn’t budged in the past two decades, despite everything we’ve learned over the years about how to lead change.

Clearly, businesses need a new model for transformation. In this article the authors present one based on research with dozens of leading companies that have defied the odds, such as Ford, Dell, Amgen, T-Mobile, Adobe, and Virgin Australia. The successful programs, the authors found, employed six critical practices: treating transformation as a continuous process; building it into the company’s operating rhythm; explicitly managing organizational energy; using aspirations, not benchmarks, to set goals; driving change from the middle of the organization out; and tapping significant external capital to fund the effort from the start.

Lessons from companies that are defying the odds

Idea in Brief

The problem.

Although companies frequently engage in transformation initiatives, few are actually transformative. Research indicates that only 12% of major change programs produce lasting results.

Why It Happens

Leaders are increasingly content with incremental improvements. As a result, they experience fewer outright failures but equally fewer real transformations.

The Solution

To deliver, change programs must treat transformation as a continuous process, build it into the company’s operating rhythm, explicitly manage organizational energy, state aspirations rather than set targets, drive change from the middle out, and be funded by serious capital investments.

Nearly every major corporation has embarked on some sort of transformation in recent years. By our estimates, at any given time more than a third of large organizations have a transformation program underway. When asked, roughly 50% of CEOs we’ve interviewed report that their company has undertaken two or more major change efforts within the past five years, with nearly 20% reporting three or more.

• Michael Mankins is a leader in Bain’s Organization and Strategy practices and is a partner based in Austin, Texas. He is a coauthor of Time, Talent, Energy: Overcome Organizational Drag and Unleash Your Team’s Productive Power (Harvard Business Review Press, 2017).
• PL Patrick Litre leads Bain’s Global Transformation and Change practice and is a partner based in Atlanta.

Partner Center

Journal of Materials Chemistry A

Research progress in o3-type phase fe/mn/cu-based layered cathode materials for sodium ion batteries.

* Corresponding authors

a School of Chemical Engineering, Sichuan University, Chengdu, China E-mail: [email protected]

b School of Mechanical Engineering, Chengdu University, Chengdu, China

c School of Materials Science and Engineering, Henan Normal University, XinXiang, China

d The Key Laboratory of Life-Organic Analysis, Key Laboratory of Pharmaceutical Intermediates and Analysis of Natural Medicine, School of Chemistry and Chemical Engineering, Qufu Normal University, China

Sodium ion batteries have become one of the research hotspots in the field of energy storage. Due to their comprehensive advantages in specific capacity, the working voltage, and cost, layered oxides have become one of the most promising cathode materials. Among them, O3-type materials show higher energy density and capacity in full cells. Fe/Mn/Cu-based materials have more advantages than other layered oxides in terms of cost and resource. This review focuses on layered oxide cathode materials including Na x MnO 2 , Na x FeO 2 , Na x Fe y Mn 1− y O 2 , and Na x Mn 1− y − z Fe y Cu z O 2 . The research status with respect to competitive advantages, existing challenges, and solution strategies was systematically analyzed. Furthermore, the effects of phase transition, and air stability of the layered oxide cathode on the electrochemical performance were discussed. Based on the in-depth analysis of modification methods, promising optimization strategies of electrochemical performance were proposed, hoping to provide guidance for the future design of O3-type Na x Mn 1− y − z Fe y Cu z O 2 materials.

• This article is part of the themed collection: Journal of Materials Chemistry A Recent Review Articles

Article information

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Y. Liu, D. Wang, H. Li, P. Li, Y. Sun, Y. Liu, Y. Liu, B. Zhong, Z. Wu and X. Guo, J. Mater. Chem. A , 2022,  10 , 3869 DOI: 10.1039/D1TA10329F

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Glucocorticoids reprogram the mitochondrial metabolism of macrophages, resulting in increased and sustained production of the anti-inflammatory metabolite itaconate and, as a consequence, inhibition of the inflammatory response.

• Jean-Philippe Auger
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Cell-type-resolved mosaicism reveals clonal dynamics of the human forebrain

Using mosaic variant barcode analysis, clonal dynamics of specific cell types are deconvolved in the human forebrain.

• Changuk Chung
• Xiaoxu Yang
• Joseph G. Gleeson

Phononic switching of magnetization by the ultrafast Barnett effect

Ultrafast light-induced driving of phonons at resonance in a substrate facilitates the permanent reversal of the magnetic state of a material mounted on it.

• C. S. Davies
• F. G. N. Fennema
• A. Kirilyuk

Distal colonocytes targeted by C. rodentium recruit T-cell help for barrier defence

The murine enteropathogen Citrobacter rodentium targets a specific subset of absorptive intestinal epithelial cells in the mid–distal colon, which stimulate T cells to produce sustained IL-22 signals to mitigate further spread of the pathogen.

• Carlene L. Zindl
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FSC-certified forest management benefits large mammals compared to non-FSC

Camera-trap images of 55 mammal species in 14 logging concessions in western equatorial Africa reveal greater animal encounter rates in FSC-certified than in non-certified forests, especially for large mammals and species of high conservation priority.

• Joeri A. Zwerts
• E. H. M. Sterck
• Marijke van Kuijk

Ligand efficacy modulates conformational dynamics of the µ-opioid receptor

Studies on the µ-opioid receptor using fluorescent labelling of intracellular residues and energy transfer experiments in the presence of different ligands with or without G-protein binding reveals conformational changes that correlate to ligand efficacy.

• Jiawei Zhao
• Matthias Elgeti
• Chunlai Chen

Direct observation of a magnetic-field-induced Wigner crystal

A magnetic-field-induced Wigner crystal in Bernal-stacked bilayer graphene was directly imaged using high-resolution scanning tunnelling microscopy and its structural properties as a function of electron density, magnetic field and temperature were examined.

• Yen-Chen Tsui
• Ali Yazdani

A hybrid topological quantum state in an elemental solid

A hybrid topological phase of matter is discovered in the simple elemental-solid arsenic and explored using tunnelling microscopy, photoemission spectroscopy and a theoretical analysis.

• Md Shafayat Hossain
• Frank Schindler
• M. Zahid Hasan

Terahertz electric-field-driven dynamical multiferroicity in SrTiO 3

We demonstrate the emergence of magnetism induced by a terahertz electric field in SrTiO 3 .

• M. Pancaldi

Bitter taste receptor activation by cholesterol and an intracellular tastant

Cryo-electron microscopy structures of the type 2 taste receptor TAS2R14 in complex with Ggust and Gi1 identify cholesterol as an orthosteric agonist and the bitter tastant cmpd28.1 as a positive allosteric modulator and agonist.

• Yoojoong Kim
• Ryan H. Gumpper
• Bryan L. Roth

Necroptosis blockade prevents lung injury in severe influenza

A newly developed RIPK3 inhibitor blocks necroptosis of lung cells, reduces lung inflammation and prevents mortality in a mouse model of influenza A virus infection.

• Avishekh Gautam
• David F. Boyd
• Siddharth Balachandran

FOXO1 is a master regulator of memory programming in CAR T cells

The transcription factor FOXO1 has a key role in human T cell memory, and manipulating FOXO1 expression could provide a way to enhance CAR T cell therapies by increasing CAR T cell persistence and antitumour activity.

• Alexander E. Doan
• Katherine P. Mueller
• Evan W. Weber

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How pregnancy may speed up the aging process

The fatigue and pangs of pregnancy have made many women feel older than their years. Now there’s new research that suggests pregnancy may, in fact, accelerate the aging process.

Two new studies of genetic markers in the blood cells of pregnant women suggest that their cells seem to age at an exaggerated clip, adding extra months or even years to a woman’s so-called biological age as her pregnancy progresses.

But one of the studies also suggests this process may reverse itself once a woman gives birth, rewinding time so that some mothers’ cells seemingly end up biologically younger afterward than they’d been during gestation, especially if a mother breastfeeds her baby.

Together, the studies underscore how physically demanding pregnancy is. But they also raise important questions about aging itself and whether it really can be sped up, slowed or reversed by pregnancy.

Aging in pregnancy

The newest of the studies , published today in Proceedings of the National Academy of Sciences, found pregnancy “has a big impact on a woman’s body” and biological age, said Calen P. Ryan, an associate research scientist at the Columbia Aging Center at Columbia University in New York, who led the new research.

In it, scientists used several different biological-age “clocks” and other measures to analyze DNA markers in blood samples. These clocks aren’t timepieces but, instead, algorithms, developed using artificial intelligence programs, that examine the patterns of specialized chemical markers found on the outside of some genes. These markers accumulate and change in response to our age, health and lifestyles, a process known as epigenetics.

The algorithms can use these epigenetic markers to estimate the relative age of cells. This measure, often referred to as biological age, can differ from someone’s chronological age, which just means how long he or she’s been alive.

In the new study, the researchers checked blood samples from 825 young women in the Philippines, all born in the same year. Some had been or were pregnant, and others hadn’t conceived. Analyzing these samples, the epigenetic clocks broadly agreed that the biological age of the young women who’d been or were pregnant tended to be higher than that of the others, by at least several months, even after the researchers controlled for economic disparities and other social and health factors.

Pregnancy as a stress test

Similarly, the other new study, published in March in Cell Metabolism , used several different epigenetic clocks to estimate the changing internal age of pregnant women at several points during their pregnancies.

“We were very interested in looking at the impacts of pregnancy as a naturally occurring stress test,” said Kieran J. O’Donnell, an assistant professor at the Yale Child Study Center and Yale School of Medicine, who oversaw one of the new studies.

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With blood samples from 119 pregnant American women and five different clocks, the researchers tracked the epigenetic changes related to the women’s biological age, starting early in gestation and ending three months after they’d given birth.

The clocks again agreed that pregnancy seemed to be aging the incipient moms as they approached full term, making their blood cells’ DNA appear to be as much as two years older than it had been earlier in the pregnancy.

More encouraging, though, O’Donnell said, is that this aging seemed to reverse for most of the women within three months after birth. In general, their patterns of DNA markers soon reverted to an earlier, more-youthful state, and for some new moms who’d breastfed exclusively in the first three months postpartum, overshot the mark, leaving them apparently “younger” biologically than before, by as much as eight years, the study’s authors wrote, “indicating a pronounced reversal of biological aging.”

Disagreement about aging

But some researchers who study aging, longevity and epigenetics are skeptical of the studies’ findings and conclusions. “It seems unlikely to me that pregnancy induces a whole-body acceleration of biological aging which is then reversed soon after pregnancy,” said Matt Kaeberlein, a longtime longevity researcher who serves as CEO of Optispan, a company that promotes longevity and produces the “Optispan” podcast.

Charles Brenner, who studies metabolism, cancer and aging at the Beckman Research Institute of the City of Hope National Medical Center in California was blunter in an email. “100%, it’s a misuse of aging biomarkers,” he wrote.

Both scientists, as well as others who’ve discussed the studies online, speculate that the epigenetic shifts seen during pregnancy probably reflect the profound physiological demands of carrying a child. They’re “a transient response to the stress of pregnancy, particularly in the immune system,” Kaeberlein said.

What they aren’t is evidence that pregnant women suddenly get older and then younger, these researchers say, or experience lasting effects that could directly shorten or lengthen their life spans.

But the cellular changes being picked up and analyzed by the epigenetic clocks might someday be useful health indicators. If a pregnant woman’s epigenetic markers don’t soon bounce back once she’s no longer pregnant, she and her doctor might want to closely monitor her blood pressure, blood sugar and other standard measures of health, not because she suddenly seems older after becoming pregnant, but because, Ryan said, “pregnancy is such a big deal, physically.”

Do you have a fitness question? Email [email protected] and we may answer your question in a future column.

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Watch your garden glow with new genetically modified bioluminescent petunias

Sasa Woodruff

A long exposure photo of Firefly petunias, which are genetically modified to produce their own light through bioluminescence Sasa Woodruff/Boise State Public Radio hide caption

A long exposure photo of Firefly petunias, which are genetically modified to produce their own light through bioluminescence

Keith Wood, Ph.D. spent most of his career in pharmaceutical research in molecular and chemical biology, using his work with bioluminescence to understand how molecules interacted with diseases. His work started as a graduate student when the team he was on inserted a firefly gene into a tobacco plant.

It was a small plant and couldn't sustain light without the addition of a substrate. It wasn't something a consumer would buy, but it was good for understanding pathways within an organism.

Now, about 40 years after that first plant, Wood and his company in Ketchum, Light Bio, are marketing a garden petunia with a twist: it glows in the dark.

View this post on Instagram A post shared by Alexandra L. Woodruff (@trowelandfork)

"People don't think about science as just bringing joy to our lives," Wood said, "We thought we could do something really special here. We could create a kind of decorative plant that was really just enjoyment, just bringing a kind of magic into our lives."

Scientist Keith Wood stands in his Ketchum home with a photo of a tobacco plant modified with a firefly gene Sasa Woodruff/Boise State Public Radio hide caption

Scientist Keith Wood stands in his Ketchum home with a photo of a tobacco plant modified with a firefly gene

The petunia with bright, white flowers looks like something you'd buy in spring at a garden nursery. But, when the lights are turned out, the petals slowly start lighting up with a greenish, white glow. The plant is always glowing, it's just our eyes that need to adjust to see the light. The newest buds are the brightest and punctuate the glowing flowers.

"That's why we call it the Firefly Petunia. Because these bright buds resemble fireflies sitting on top of the plant.," Wood explained.

And despite its name, this plant doesn't have any firefly genes, rather four genes from a bioluminescent mushroom and a fifth from a fungi.

"The first gene takes a metabolite and turns it into an intermediate," Wood explained, "The second gene takes the intermediate and turns it into the actual fuel for the bioluminescence. The third gene is what actually makes the light. And then the last gene takes the product from the light reaction and recycles it back to the starting point."

This cycle is self-sustaining, which means it shines brightly and doesn't need an extra chemical like the tobacco plant did to light up.

"The [firefly] gene was functional, but it didn't connect seamlessly into the natural metabolic processes," Wood said.

"You've got glow, but it was a weak glow. Not satisfying at all."

Petunia approval paperwork

It took about 10 years to go from development to approval from the U.S. Department of Agriculture last fall.

The plants went on sale online in February and the first ones were shipped out this week.

Diane Blazek, the executive director of the National Garden Bureau, an educational nonprofit, says customers are always looking for the next new plant and petunias are a guaranteed bestseller.

"Grandma grew petunias, but oh, look, now I've got a petunia that glows in the dark. So, this is really cool," Blazek said.

The Firefly Petunia emanates light because it's been modified with genes from a bioluminescent mushroom Sasa Woodruff/Boise State Public Radio hide caption

The Firefly Petunia emanates light because it's been modified with genes from a bioluminescent mushroom

She doesn't think that the fact that it's genetically modified will affect customers buying it because there's a precedent.

Seven years ago, an orange petunia modified with a maize gene showed up in gardens and nurseries in Europe and the U.S. The plant was never supposed to leave a closed lab but somehow ended up in lots of gardens. Regulators eventually asked people to destroy the plants and seeds.

"Overwhelmingly, the response was, wait a minute, it's a petunia. We're not eating it. The orange gene came from maize. Why? Why can't we plant this?" Blazek remembered.

Eventually, regulators approved the plants in the U.S.

Chris Beytes, at Ball Publishing, who oversees several horticulture publications, said the Firefly Petunia could open up gardening to new customers.

"If you buy your first plant because it glows in the dark or it's dyed pink, your second and third and 100th plant may be the traditional stuff. You never know," Beytes said. "Anything that creates excitement around flowers and plants. I'm all for it."

The Firefly Petunia may not have practical implications for things like drug advances or crop production, but for Wood this petunia is transcendent.

"There's something magical about seeing this living presence, this glowing vitality coming from a living plant that in person gives a kind of magical experience that you just can't see in a photograph.

And this summer, that magic could be sitting on the patio watching your garden glow from the light of a petunia.

Read our research on: Gun Policy | International Conflict | Election 2024

Regions & Countries

About 1 in 4 u.s. teachers say their school went into a gun-related lockdown in the last school year.

Twenty-five years after the mass shooting at Columbine High School in Colorado , a majority of public K-12 teachers (59%) say they are at least somewhat worried about the possibility of a shooting ever happening at their school. This includes 18% who say they’re extremely or very worried, according to a new Pew Research Center survey.

Pew Research Center conducted this analysis to better understand public K-12 teachers’ views on school shootings, how prepared they feel for a potential active shooter, and how they feel about policies that could help prevent future shootings.

To do this, we surveyed 2,531 U.S. public K-12 teachers from Oct. 17 to Nov. 14, 2023. The teachers are members of RAND’s American Teacher Panel, a nationally representative panel of public school K-12 teachers recruited through MDR Education. Survey data is weighted to state and national teacher characteristics to account for differences in sampling and response to ensure they are representative of the target population.

We also used data from our 2022 survey of U.S. parents. For that project, we surveyed 3,757 U.S. parents with at least one child younger than 18 from Sept. 20 to Oct. 2, 2022. Find more details about the survey of parents here .

Here are the questions used for this analysis , along with responses, and the survey methodology .

Another 31% of teachers say they are not too worried about a shooting occurring at their school. Only 7% of teachers say they are not at all worried.

This survey comes at a time when school shootings are at a record high (82 in 2023) and gun safety continues to be a topic in 2024 election campaigns .

Teachers’ experiences with lockdowns

About a quarter of teachers (23%) say they experienced a lockdown in the 2022-23 school year because of a gun or suspicion of a gun at their school. Some 15% say this happened once during the year, and 8% say this happened more than once.

High school teachers are most likely to report experiencing these lockdowns: 34% say their school went on at least one gun-related lockdown in the last school year. This compares with 22% of middle school teachers and 16% of elementary school teachers.

Teachers in urban schools are also more likely to say that their school had a gun-related lockdown. About a third of these teachers (31%) say this, compared with 19% of teachers in suburban schools and 20% in rural schools.

Do teachers feel their school has prepared them for an active shooter?

About four-in-ten teachers (39%) say their school has done a fair or poor job providing them with the training and resources they need to deal with a potential active shooter.

A smaller share (30%) give their school an excellent or very good rating, and another 30% say their school has done a good job preparing them.

Teachers in urban schools are the least likely to say their school has done an excellent or very good job preparing them for a potential active shooter. About one-in-five (21%) say this, compared with 32% of teachers in suburban schools and 35% in rural schools.

Teachers who have police officers or armed security stationed in their school are more likely than those who don’t to say their school has done an excellent or very good job preparing them for a potential active shooter (36% vs. 22%).

Overall, 56% of teachers say they have police officers or armed security stationed at their school. Majorities in rural schools (64%) and suburban schools (56%) say this, compared with 48% in urban schools.

Only 3% of teachers say teachers and administrators at their school are allowed to carry guns in school. This is slightly more common in school districts where a majority of voters cast ballots for Donald Trump in 2020 than in school districts where a majority of voters cast ballots for Joe Biden (5% vs. 1%).

What strategies do teachers think could help prevent school shootings?

The survey also asked teachers how effective some measures would be at preventing school shootings.

Most teachers (69%) say improving mental health screening and treatment for children and adults would be extremely or very effective.

About half (49%) say having police officers or armed security in schools would be highly effective, while 33% say the same about metal detectors in schools.

Just 13% say allowing teachers and school administrators to carry guns in schools would be extremely or very effective at preventing school shootings. Seven-in-ten teachers say this would be not too or not at all effective.

How teachers’ views differ by party

Republican and Republican-leaning teachers are more likely than Democratic and Democratic-leaning teachers to say each of the following would be highly effective:

• Having police officers or armed security in schools (69% vs. 37%)
• Having metal detectors in schools (43% vs. 27%)
• Allowing teachers and school administrators to carry guns in schools (28% vs. 3%)

And while majorities in both parties say improving mental health screening and treatment would be highly effective at preventing school shootings, Democratic teachers are more likely than Republican teachers to say this (73% vs. 66%).

Parents’ views on school shootings and prevention strategies

In fall 2022, we asked parents a similar set of questions about school shootings.

Roughly a third of parents with K-12 students (32%) said they were extremely or very worried about a shooting ever happening at their child’s school. An additional 37% said they were somewhat worried.

As is the case among teachers, improving mental health screening and treatment was the only strategy most parents (63%) said would be extremely or very effective at preventing school shootings. And allowing teachers and school administrators to carry guns in schools was seen as the least effective – in fact, half of parents said this would be not too or not at all effective. This question was asked of all parents with a child younger than 18, regardless of whether they have a child in K-12 schools.

Like teachers, parents’ views on strategies for preventing school shootings differed by party. 

Note: Here are the questions used for this analysis , along with responses, and the survey methodology .

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‘Back to school’ means anytime from late July to after Labor Day, depending on where in the U.S. you live

Among many u.s. children, reading for fun has become less common, federal data shows, most european students learn english in school, for u.s. teens today, summer means more schooling and less leisure time than in the past, about one-in-six u.s. teachers work second jobs – and not just in the summer, most popular.

About Pew Research Center Pew Research Center is a nonpartisan fact tank that informs the public about the issues, attitudes and trends shaping the world. It conducts public opinion polling, demographic research, media content analysis and other empirical social science research. Pew Research Center does not take policy positions. It is a subsidiary of The Pew Charitable Trusts .

UC experts present at national neurology conference

University of Cincinnati researchers will present abstracts at the American Academy of Neurology annual meeting 2024, April 13-18 in Denver, Colorado.

Two-component treatment leads to improvement for patients

Hani Kushlaf, MD. Photo/University of Cincinnati.

Late-onset Pompe disease (LOPD) is a rare, inherited genetic disease caused by the accumulation of glycogen, the body’s stored form of glucose, in muscles and other organs. Left untreated, the muscle weakness it causes can lead to the loss of the ability to walk and breathing impairment.

A research team led by UC’s Hani Kushlaf, MD, looked at the effect of a two-component enzyme replacement therapy (ERT) of drugs cipaglucosidase and miglustat (cipa+mig) compared to a single ERT drug, alglucosidase alfa (alg) and a placebo. UC researchers participated in the Phase 3 trials that led to the Food and Drug Administration approval of both ERT regimens.

“The research question was to look at the magnitude and practical significance of the effect of cip+mig versus alg using patient data from the PROPEL trial on outcomes that included motor function, pulmonary function, muscle strength, biomarkers and patient- and physician-reported quality of life,” said Kushlaf, associate professor and director of Neuromuscular Research and the Neuromuscular Disorders Division in UC’s Department of Neurology & Rehabilitation Medicine in the College of Medicine.

Patients who switched to the dual ERT regimen experienced improvement or stability across the measured outcomes with no worsening of outcomes. Those who remained on the single ERT drug plus placebo experienced worsening or stability across the measured outcomes.

“This analysis highlights the potential of cipaglucosidase+miglustat to become an important treatment option for patients with LOPD, including patients already on enzyme replacement therapy,” Kushlaf said.

This research was sponsored by Amicus Therapeutics, Inc.

Research team learns more about events following immunotherapy treatment

Luca Marsili, MD, PhD. Photo/University of Cincinnati.

Immune checkpoint inhibitors (ICIs), an immunotherapy that activates the body’s immune system to fight cancer cells, has revolutionized cancer treatment. But while boosting anti-tumor immunity, the treatments may cause severe neurological-immune related adverse events. 

“These neurological-immune-related adverse events include meningitis, encephalitis, demyelinating diseases, vasculitis, neuropathy, neuromuscular junction disorders and myopathy,” said Luca Marsili, MD, PhD, movement disorder fellow in the Department of Neurology and Rehabilitation Medicine in the University of Cincinnati College of Medicine.  

Marsili said the frequency of these adverse events, and the best way to manage them, is still largely unknown. 

A team led by Marsili and Alberto Espay, MD, reviewed reported neurological-immune-related adverse events in patients treated with immune checkpoint inhibitors at UC from 2011-2023. They found the adverse events are rare, affecting 28 patients out of 1,677 treated, or 1.66%. 

The adverse events were most often associated with melanoma treatment with pembrolizumab, a common immunotherapy treatment. 

“The adverse events were most expressed as peripheral neuropathies and encephalitis, manifesting early during treatment within a mean of 2.3 months after ICI initiation,” Marsili said. “Most ICIs, 68%, were discontinued, and in only 10.7% of cases they were restarted without complications.” 

Moving forward, the team said further research is needed to determine clinical susceptibility factors and appropriate timing of restarting ICI treatment after discontinuing due to an adverse event. They are also planning to do more detailed demographic and clinical comparisons of the 28 patients identified to have adverse events to see if there are any predictive factors like tumor type, age, sex or ethnicity. 

“This study is part of a broader project in collaboration with the University of Udine in Italy and with the Department of Internal Medicine at UC,” Marsili said. “We would like to gather a high number of participants to assess incidence/prevalence of these adverse events and also to raise awareness among neurologists on how to treat/manage them.”

Safe, effective treatment for Parkinson’s

Alberto Espay, MD. Photo/University of Cincinnati.

Alberto Espay, MD, will present findings recently published in the Lancet Neurology journal that found Parkinson’s disease medication delivered through an infusion pump is safe and effective at reducing symptoms for longer periods of time. 

Parkinson’s symptoms such as tremors, slowness and stiffness are caused by low levels of dopamine in the body. For decades, doctors have treated Parkinson’s by giving patients levodopa, the inactive substance in the brain that once converted makes dopamine.  

“Levodopa is a replacement strategy. We all make levodopa, but Parkinson's patients make less of it,” said Espay, co-principal investigator of the trial, the James J. and Joan A. Gardner Family Center for Parkinson’s Disease Research Endowed Chair in UC’s Department of Neurology and Rehabilitation Medicine and a physician at the UC Gardner Neuroscience Institute.  

Levodopa is most commonly administered orally, but this trial tested continuous, 24-hour levodopa delivery through a subcutaneous infusion pump. A total of 381 patients with Parkinson’s disease in 16 countries enrolled in the trial and were randomized to receive levodopa through the infusion pump or through traditional oral medication. 

The researchers found levodopa delivered through the infusion pump was safe and led to almost two hours a day (1.72) of additional “on time,” or the time when the medication is working and symptoms are lessened, compared to taking levodopa orally. 

“Once approved, this will become an important treatment strategy to consider for patients with Parkinson’s disease experiencing motor fluctuations not adequately controlled with medication,” he said. “Future studies will need to determine the durability of the long-term benefits and whether any safety issues could emerge, as well as how it might compare with deep brain stimulation.”

Impact Lives Here

The University of Cincinnati is leading public urban universities into a new era of innovation and impact. Our faculty, staff and students are saving lives, changing outcomes and bending the future in our city's direction.  Next Lives Here.

UC research being presented at AAN includes:

• Kushlaf presenting “ Effect Size Analysis of Cipaglucosidase Alfa Plus Miglustat Versus Alglucosidase Alfa in ERT-experienced Adults with Late-onset Pompe Disease in PROPEL .”
• Marsili and Espay presenting “ Neurological Immune-related Adverse Events of Immune Checkpoint Inhibitors: A Single-center Retrospective Study. ” 
• Espay presenting “ Efficacy of ND0612, a 24-hour Subcutaneous Levodopa/Carbidopa Infusion for People with Parkinson’s Disease Experiencing Motor Fluctuations: Subgroup-analyses from a Randomized, Controlled Phase 3 Study .”
• Stacie Demel, DO, PhD, a physician-researcher at the UC Gardner Neuroscience Institute and associate professor of clinical neurology and rehabilitation medicine in UC’s College of Medicine, presenting “ Methylation Patterns Differ Between ICH Cases and Controls .”
• Yang Yu, MD, UC medical resident/fellow, presenting “ Multiple Sclerosis in a Patient with Friedreich's Ataxia .”
• Rhonna Shatz, DO, adjunct associate professor, division director for behavioral neurology, and the Bob and Sandy Heimann Endowed Chair in Research and Education in Alzheimer’s Disease in the UC College of Medicine, presenting “ Identifying a Relationship Between Executive Dysfunction, Poor Sleep Hygiene/Sleep Apnea, and Ventriculomegaly in Cancer-related Cognitive Impairment (CRCI) ”

Featured illustration at top of brain. Photo/iStock/Onurdongel.

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