“The population, intervention and comparison components of the question, with the additional specification of types of study that will be included, form the basis of the pre-specified eligibility criteria for the review.”1
The purpose of a systematic review is to capture & review all literature published on a topic. It is recommended that date ranges be applied only when:
Ideally, studies published in all languages should be considered for a review. It is not always practical to translate studies published in other languages, however, so it is acceptable to limit study languages that may be read by the review team.
Study participants may be limited to specific groups of people or age ranges.
Includes interventions of interest and excludes any others.
Studies may be limited to a specific setting, e.g., inpatient, ambulatory, emergency, etc.
“It is rare to use outcomes as eligibility criteria: studies should be included irrespective of whether they report outcome data, but may legitimately be excluded if they do not measure outcomes of interest, or if they explicitly aim to prevent a particular outcome.”1
1. McKenzie J, Brennan S, Ryan R, Thomson H, Johnston R, Thomas J. Defining the criteria for including studies and how they will be grouped for the synthesis. In: Higgins J, Thomas J, Chandler J, et al., eds. Cochrane Handbook for Systematic Reviews of Interventions. version 6.2: Cochrane; 2021.