Research Guides: Systematic Reviews &amp; Evidence Synthesis: Exploratory Searches

The Purpose of Exploratory Searching

What is "Exploratory Searching" in Evidence Synthesis?

Exploratory searching is the process of conducting well-designed but non-comprehensive searches to help develop and refine your project idea.

Exploratory searching occurs on and off throughout the entire pre-planning and protocol writing phases.

Exploratory Searching Diagram - Text Version
Exploratory searches are an iterative process.
Start with an initial research question or idea and search for:
1. Existing evidence synthesis reviews (systematic reviews, scoping reviews, etc.)
2. In-process evidence synthesis reviews (by searching for registered protocols)
3. “Seed articles” that represent the exact types of results you are seeking to find and synthesize
4. Overall volume of results, suggesting how much screening will be necessary.
5. Background articles that can support you introduction and concept definitions
Use all of these to:
Refine your research question &
Refine your inclusion and exclusion criteria

Use those refinements of your research question to continue iterating the exploratory searches as needed throughout the protocol writing and search design phases of your project.

Why do Exploratory Searching in Evidence Synthesis?

The primary purpose is to help you develop and refine your research questions and inclusion/exclusion criteria.

Support and justify your project

Just like any research project, this project will begin with a background literature review that sets the stage for what you are doing by defining key concepts and their relevance, why the project is valuable, and provides your objectives/aims statements.

Locate existing and proposed reviews

You do not want to duplicate effort, especially since these projects are a significant commitment of time and effort. Try to locate any existing reviews on your topic as well as any protocols registered for planned review projects. There may be a similar project, yet still be justification for your own project idea or a revised version of that idea.

Refine your research question

Sometimes it is necessary to change the research question or change the review type to make the project viable and publishable. Make sure your research question is appropriate to the planned review type and the quantity and type of evidence available.

Locate "seed" articles

You will need to have a collection of "seed articles" (also called "target" or "seminal" articles) that will help inform and test your search design and inclusion/exclusion criteria. These should be examples of article that you would expect to make it through the screening process and into the final synthesis.

Assess scope

Different review types rely on different quantities and types of evidence. You do not want to find out in the middle of the project that there is far to little, far too much, or the wrong kinds of evidence for your project. You also want to get a sense of the amount of screening time necessary. A research question may need to be scoped smaller if you cannot support the needed screening time. Using limits on the search to make the results smaller will just bias the results and undermine a project. Consult a librarian if you are concerned about this.

Get ideas for project design

Locate other evidence synthesis projects that are answering similar types of questions or using the same review type, assess the quality of these projects, and determine if you can use them as examples to help guide your own process. You may be able to find examples of search design, data extraction forms, risk of bias assessment, and more that can help you refine your protocol and overall process.

General Tips on Doing Exploratory Searching

Develop a well-designed but non-comprehensive search strategy to help develop and refine your project idea.

Beginner: Search Techniques Tutorial
Tutorial on how to use AND & OR to create searches in library databases.
Advanced: Search Techniques Tutorial
Tutorial on how to use the NOT operator, truncation, phrase searching, and nesting in library databases.

How to Locate Existing and Planned Reviews

Locate Existing Review Articles

To locate existing review articles, run your reasonably thorough search strategy in both your selected primary database and general database.

Then try the following methods, one at a time:

If the database has it, apply the "systematic review" or "reviews" filter
Add AND (review) to your search
Add AND ("systematic review" OR "meta-analysis" OR "scoping review") to your search

What if you locate an existing review on your topic?

How old is the review? Does it warrant an update?
Was the review conducted well or are there major flaws that you could improve upon?
Is there an adjustment to your research question that is valuable and would not duplicate their results?
Can you learn something from the search design or other processes in this review that can help you conduct your own review?

Locate Proposed Review Articles

Search for publicly registered review protocols. If you find one on your research question, then another team is already working on a review on your topic.

Places to search include:

PROSPERO
Register protocols for systematic reviews broadly relevant to health outcomes. There are separate registries for human only and animal only projects. Only accepts systematic review protocols.
OSF Registries
General registration space for protocols for all types of reviews and all disciplines.
PROCEED
Register protocols for all types of evidence synthesis relevant to the environmental sector (science, management and policy).
figshare
General registration space for protocols for all types of reviews and all disciplines.
INPLASY
Systematic and scoping review protocols in interventions, diagnostic accuracy, prognostic factors, epidemiological characteristics, preclinical studies, sport performance, as well as methodological reviews and pedagogical reviews.
Directory of Open Access Preprint Repositories
A list of preprint repositories with access links in a wide variety of fields. Identify the preprint repository most relevant to your subject.
- Use a simplified version of your search strategies (just 1-3 synonyms per concept) plus the terms ("systematic review" OR "meta-analysis" OR "scoping review"). This should pick up both any protocols or preprints of reviews on the topic.
- If you get a large number of results, try searching ("systematic review" OR "meta-analysis" OR "scoping review") in the title only.

Journal/Repositories that Specialize in Evidence Synthesis: There are journals and repositories that specialize in publishing or collecting evidence synthesis projects. Some of these are field specific and some are not. Ask disciplinary experts and librarians for recommendations.
- Some of the best known include:
  - Campbell Systematic Reviews (social sciences)
  - Cochrane Reviews (healthcare and medicine)
  - Collaboration for Environmental Evidence (CEE)
  - Systematic Reviews for Animals and Food (SYREAF)
  - What Works Clearinghouse (education)

What Are "Seed" Articles?

Worksheet - Seed Article Term Harvesting
Use this worksheet to help you harvest keywords and subject headings from your seed articles for use in your search design.

Seed articles (also called "target" or "seminal" articles) are 2-8 articles on your topic that you think will make it though your screening process.

If you cannot find at least a couple articles that you think will make it though your screening process (applying inclusion/exclusion criteria), then you are at risk of producing an evidence synthesis project than cannot make any practice or policy recommendations.
- It can be valuable to conduct and publish an evidence synthesis project demonstrating a lack of evidence, but you should check with program advisors or potential publishers to see if they accept or publish those types of projects.

Use these articles to refine your inclusion/exclusion criteria, research question, and your term list of keywords and controlled vocabulary.
- Ask yourself: Is this article going to make it through my inclusion/exclusion criteria? Does it meet my research goal/aim? If not, what needs to change (re-scope the question, alter the screening criteria, refine my concept definitions, discard the article)?
- Ask yourself: Do I use all the relevant keywords from this article in my search strategy? What controlled vocabulary is applied to this article and should those be in my search strategy?

Your final comprehensive search strategy should locate these seed articles!
- If it doesn't, contact a librarian for further assistance.
Seed articles can be used to communicate with librarians and other experts about what types of evidence meet your goals.

Get Expert Help

The CSU Libraries offers expert evidence synthesis project support for systematic reviews, scoping reviews, evidence maps, and more.

Request a consultation on methods and process
Request a search strategy review
Request a classroom, lab group, or other small group training
Attend a scheduled workshop

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