Basics of Systematic Reviews

A guide to evidence synthesis

Step 3a: Conduct Your Literature Searches

In the third step, you and your team will develop a search string to locate articles that will help answer your research question or topic. Keep in mind that a librarian can assist with this step.  To develop a successful search string, you will:

  • Consult your subject librarian.
  • Identify the main concepts of your research topic.
  • Select the databases your team will search (choose at least 3).
    • Consider options for databases outside UTSA subscriptions
      • Collaborators, adjuncts, alumni access, & etc.
    • Check what databases related SRs have used.
  • List the terms that describe each concept.
  • Do some preliminary searching: review the abstracts you find for relevant keywords.  Add those terms to your search string.
  • Add terms from each individual database's subject headings/controlled vocabulary (for example, MeSH is PubMed's controlled vocabulary. Some databases may not have a controlled vocabulary).
  • Use field tags to tell the database where to search for terms (title, title & abstract, full text, etc.).
  • Combine selected terms with Boolean operators to develop a search string (a common concept search structure in the health sciences is: population AND intervention AND outcome)
  • Translate your search string to each database.
  • Save a copy of your search strategies.

Step 3b: Searching Grey Literature

In order to perform a comprehensive search of the available literature, it's often recommended (though not required) to search grey literature.  Grey literature is research and other types of information produced outside of academic or traditional publishing channels like scientific journals.   The inclusion of grey literature sources can make your systematic review more robust. Examples of grey literature include:

Completed clinical trials Research studies that test a medical, surgical, or behavioral intervention in people.  
 
Conference Proceedings (can include posters & papers)
Government Reports International, national, and local governmental documents.
Preprints A full draft of a research paper that is shared publicly before it has been peer reviewed.
Statistical Data Often considered grey literature as they are published by government, research organizations and researchers, not by traditional publishing sources.
White Papers A research-based report that examines a topic and offers potential solutions to a problem.
Guidelines and Position Papers Issued by organizations (such as American Cancer Society) produced outside of traditional publishing and distribution channels.

There are a number of places you can search for grey literature, including:

Step 3c: Applying PRISMA

There are guidelines available for suggested reporting items when documenting your search in the written portion of your review.  For this step, review the PRISMA-S checklist, which is the search reporting extension of PRISMA.  Make sure to specify the dates when each resource was last searched.  It's important to document the full search strategy used in each database, register, or website.  Any applied limiters and filters should be documented as well and included in an appendix.