An important part of the SR process is defining the inclusion and exclusion criteria. These criteria are determined after setting the research question and before the search process begins (you can still conduct scoping searches to determine the appropriate criteria for your study).
Information about the inclusion and exclusion criteria is usually recorded at the protocol and the methods section of the systematic review.
Examples of common inclusion and exclusion criteria:
- Language of publications: The included studies should not be restricted by specific language (usually limiting solely to English language publications) as this may introduce bias. In a thorough review, studies in other languages should be translated if possible. However, if translation is not possible, this should be noted as a limitation of the review.
- Publication date: Limit your search to specific date/year ranges. how far back do you wish to search for information? You have to provide the reason for restricting your search by publication date (e.g. conducting an update for an existing review).
- Settings: The studies included or excluded based on where the participants were located (e.g. hospital, nursing home, school).
- Study designs: Limit your search to quantitative or qualitative studies, a mixture of both, or a specific type of study such as randomized controlled trials. Justify the choice of the study designs by considering their appropriateness to the review question and the potential for bias.
- Types of interventions: Describe the intervention being investigated. What are the experimental and control (comparator) interventions of interest? Will studies including only part of the intervention be included?
- Types of participants: The included studies are addressing a specific group of participants: by age group (e.g. neonate, child, adolescent, adult, older adult, etc.), by gender, by ethnicity, or by diagnosis.
- Types of publications: SR usually synthesize original studies. Studies published in ‘grey’ literature sources such as reports, dissertations, editorials, essays, letters, conference papers should be considered if they are relevant to your topic.
Refer to the Common Inclusion/Exclusion Criteria developed by the University of Melbourne for more inclusion and exclusion criteria.