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Systematic Review Service

Partnering with MSK community members interested in systematic and related reviews

Search for Evidence

The scope of a systematic review is wider than that of a typical literature search, and it returns more irrelevant literatureUnlike many literature searches, a systematic review search casts a wide net to bring in the information relevant to your topic.

  • Specific (precise, narrow) searches: These search strategies return mainly literature that is relevant to the topic. However, they may miss a large volume of relevant results.
  • Sensitive (comprehensive, wide) searches return the majority of relevant literature, but also return a large number of irrelevant results.

Another way to think of a search strategy is a funnel. The wider the funnel, the more results are captured, but the more that must be screened by your team. But if the funnel is not wide enough, important results may be missed, and this is not a systematic search.

The goal of the systematic review search is to balance specificity and sensitivity. Your MSK librarian will work with your team to achieve this as successfully as possible given the scope of your project.

Image courtesy of the Karolinska Institutet University Library, CC BY-SA 4.0.

How the MSK Library Can Help

According to the Cochrane Handbook for Systematic Reviews of Interventions, systematic reviews should search the databases MEDLINE (a part of PubMed), Embase, and Cochrane Central Register of Controlled Trials (CENTRAL). Depending on the topic of your review, adding additional databases may also be warranted, especially discipline- or geographic-specific sources.

MSK librarians:

  • Consult with the review team to select databases to search.
  • Work with review teams to build a search that appropriately balances specificity and sensitivity using correct database syntax.
  • Request a colleague perform a Peer Review of Electronic Search Strategies (PRESS) prior to translating the search strategy to additional databases.
  • Translate the search to all selected databases.
  • Run and document the search strategy and number of results for each database.

Systematic reviews can benefit from searching beyond traditional databases. According to AMSTAR, a systematic review methodological quality assessment tool, a comprehensive literature search strategy means also having:

  • Searched the reference lists/bibliographies of included studies.
  • Searched trial/study registries.
  • Included/consulted content experts in the field.
  • Searched for grey literature when relevant (like government documents, white papers, reports, and clinical trial records).

Your MSK librarian can help you perform forward and backward reference list searches of the studies included in your review, search trial registries like ClinicalTrials.gov, handsearch journals, and find grey literature like government documents, white papers, and more.

Learn more about supplemental searching.

Almost as soon as a systematic review search is run, the results start becoming outdated. Because of this, some journals require systematic review searches to have been run within six months to a year of publication.

When you are nearing submission to a journal, reach out to your MSK librarian. If needed, they can perform a search update, upload new results to Covidence, and provide updated methods.

Search updates can be tricky to perform, and sorting through additional results adds considerable work to the review process. Having sufficient time and staff to perform a review from the start reduces the likelihood that updates will be needed. 

Systematic review searches must be documented following the PRISMA extension for searching. Your MSK librarian will include all required documentation to detail the search in a transparent, replicable manner.

This documentation becomes the search methods section of your review, and the searches themselves are included in supplemental material. Your MSK librarian is listed as a co-author of the resulting publication.

How Covidence Can Help

Once your MSK librarian has run the searches for your review, they will upload all the results to Covidence. Covidence will then remove duplicates and automatically begin compiling your PRISMA Flow Diagram.

Learn more about how Covidence manages duplicate records: