Reading focus
Syllabus: How Do We Combine Evidence Across Studies?
Trace the connections between the review question, eligible studies, searching and the form of synthesis.
Why you’re reading it. Treat a review as a designed investigation with a defensible scope.
A question to consider. For a review of whether group study improves learning, what differences in participants, comparison activities and outcomes would you specify before searching?
Why this reading
A review makes consequential decisions before it produces a conclusion. Siddaway and colleagues connect a research question to eligibility, searching, appraisal and synthesis, treating a review as an argument built from a defined body of evidence.
Before you read
A systematic review uses explicit methods to identify and evaluate relevant work. Meta-analysis statistically combines results; it is one possible part of a review. A study, its several reports and its several findings are different units.
Read for
- Follow how narrowing a question changes the evidence that can answer it and the conclusions that remain possible.
- Distinguish an organized catalogue, a count of significant results and a synthesis that explains a pattern.
- Examine decisions about unpublished work, eligibility changes and the quality of included evidence.
Consider afterwards
- Two reviews reach different conclusions about the same broad topic. Which decisions would you compare before attributing the disagreement to their statistical methods?
Editorial context
This is methodological guidance rather than a validation of one universal review procedure. Its examples of databases, software and reporting standards reflect the publication period. PRISMA 2020 subsequently updated reporting guidance; transparent reporting helps appraisal but does not make the underlying evidence unbiased.