Skip to Main Content
Kornhauser Health Sciences Library

Systematic Reviews and Evidence Syntheses



According to the CDC, a librarian (expert searcher) trained in systematic reviews is “integral” to your search. The librarian will be responsible for:

  • Developing the search strategy based on your fully developed research question.
  • Conducting the search.
  • Documenting the search strategies in the Methods section of the review report.

Do not attempt to take on these responsibilities yourself.

  • In advanced reviews, the study identification and selection process is a significant portion of a manuscript's methods section.
  • To achieve the required levels of transparency and reproducibility, this process should be approached with the same rigor as the development of any original research project's methodology.
  • Your research question, review type, team composition, project timeline, and other practical limitations will all inform your approach.


You'll need to have documented your process in sufficient detail that you can report it accurately when writing your manuscript, so it's important to keep notes on:

  • Which databases and any other sources you searched
  • The queries you used in each
  • Any limiters or filters
  • The date you ran the search
  • How many results were retrieved by each database
  • Total combined results before and after extracting duplicates

Bibliographic databases

To gather all relevant literature on a research topic for synthesis, comprehensive searches are conducted in multiple databases.

  • The CDC recommend at least 3 standard medical databases (PubMed, CINAHL, Embase, etc.)

For health sciences reviews, we typically use:

Additionally, we typically use at least one subject-specific database, as appropriate. Examples include:

Grey literature

"Grey literature" refers to research material not included in standard health science that may contain important information on your evidence synthesis topic. This includes:

  • Government reports
  • Conference proceedings
  • Theses and dissertations
  • Unpublished clinical trial protocols

The CDC recommend at least 2 grey literature resources.

Recording your search process and sources remains important to preserve transparency and replicability.