Defining the criteria for including studies and how they will be grouped for the synthesis

Joanne E. McKenzie, Sue E. Brennan, Rebecca E. Ryan, Hilary J. Thomson, R.V. Johnson, James Thomas

Research output: Chapter in Book/Report/Conference proceedingChapter (Book)Researchpeer-review

116 Citations (Scopus)


This chapter describes the processes by which the structure of the synthesis can be mapped out at the beginning of the systematic review, and the interplay between the review question, considerations for the analysis and their operationalization in terms of eligibility criteria. Decisions about which studies to include (and exclude), and how they will be combined in the review’s synthesis, should be documented and justified in the review protocol. The chapter focuses on the review population, intervention(s), comparator(s) and outcomes (PICO) and the PICO for each synthesis as a basis for specifying which studies should be included in the review and planning its syntheses. These PICOs should relate clearly and directly to the questions or hypotheses that are posed when the review is formulated and will involve specifying the population in question, and a set of comparisons between the intervention groups.

Original languageEnglish
Title of host publicationCochrane Handbook for Systematic Reviews of Interventions
EditorsJulian P.T. Higgins, James Thomas, Jacqueline Chandler, Miranda Cumpston, Tianjing Li, Vivian A. Welch, Matthew J. Page
Place of PublicationChichester UK
PublisherJohn Wiley & Sons
Number of pages33
ISBN (Electronic)9781119536611
ISBN (Print)9781119536628
Publication statusPublished - 5 Oct 2019


  • Eligibility criteria
  • Intervention groups
  • Pico construct
  • Review protocol
  • Review question
  • Review’s synthesis
  • Systematic review

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