PRISMA

PRISMA — Preferred Reporting Items for Systematic Reviews and Meta-Analyses — is the reporting standard for systematic reviews. It is a reporting guideline rather than a methodology: it specifies what must be disclosed so readers can judge how the review was conducted, not how to conduct it.

Its two components are a checklist covering title, abstract, rationale, eligibility criteria, information sources, search strategy, selection process, data items, risk-of-bias assessment, synthesis methods and results, and the flow diagram that tracks records through identification, screening, eligibility and inclusion.

The flow diagram is what reviewers examine first, and the numbers must reconcile: records identified, duplicates removed, records screened, records excluded, full texts assessed, full texts excluded with reasons, and studies included. The 2020 update revised the diagram to accommodate searches of registers and other sources, so cite the version you followed.