Table 1 Definitions of terms used in Figure 1

A defined and reproducible approach to efficiently identify existing systematic reviews for possible use in conducting a newly proposed systematic review, including updates.

Assess relevance

Methods by which existing systematic reviews identified in Step 1 can be evaluated as to whether they are similar enough to the newly proposed review to obviate the need for conducting one or several steps in undertaking the newly proposed review. Relevance evaluation considers how well the existing reviews’ research questions and inclusion/exclusion criteria for population, interventions, comparators, outcomes, settings, and study designs match those of the new systematic review, and how recently existing reviews’ literature searches were concluded. Use ‘almost’ relevant SR(s) when selecting, developing, and/or refining questions and providing context for a newly proposed systematic review (that is, Contextual Use) and scan references to check new search results.

Assess quality of existing SR(s)

Methods by which relevant existing systematic reviews can be evaluated for quality of methodological approach, using AMSTAR or other commonly used tools, with a focus on potentially incorporating only reviews meeting certain quality criteria into the proposed review [4, 5].

Determine appropriate use and incorporate existing SR(s)

Methods by which to determine appropriate uses for relevant, high-quality existing systematic reviews in the proposed review. Incorporate existing SR(s) or use information from existing systematic reviews to supplement or supplant one or more activities that would be conducted from scratch for the newly proposed review. Use of existing systematic reviews may include: 1) using the existing systematic review(s)’ listing of included studies as a quality check for the literature search and screening strategy conducted for the new review (Scan References); 2) using the existing systematic review(s) to completely or partially provide the body of included studies for one or more key questions in the new review (Use Existing Search); 3) using the data abstraction, risk of bias assessments, and/or analyses from existing systematic reviews for one or more key questions in the new review (Use Data Abstraction/Syntheses); or 4) using the existing systematic review(s), including conclusions, to fully or partially answer one or more key questions in the new review (Use Complete Review).

Report methods and results from using existing SR(s)

Standards for reporting the rationale for incorporating existing systematic reviews and the methods by which specific existing systematic reviews were located, assessed, and incorporated into the current systematic review. Standards for reporting results in the current systematic review that rely on evidence and/or analysis from existing systematic reviews and caveats or limitations associated with that approach; guidance about discussing how findings of the current systematic review compare and contrast with those of existing relevant systematic reviews.