Participant-data review overview — Systematic review with individual participant data meta-analysis

Question through participant-level synthesis

Flow diagram

Steps

Question

Define the review question, intended decision and eligibility framework. Use PICO for intervention comparisons, PCC for scoping, or test/condition/clinical-role definitions for accuracy reviews.

Protocol and registration where applicable

Write the planned eligibility, search, selection, extraction, appraisal and synthesis methods before conducting the review. Record registration where eligible, or a public protocol location, and date subsequent amendments.

Identify studies

Choose information sources and supplementary search routes, retain reproducible strategies and dates, and plan an update search before final interpretation.

Obtain data

Request eligible study datasets under appropriate agreements. Track supplied, declined, pending and unavailable data separately; plan what aggregate-only evidence can contribute.

Reconcile and harmonize

Compare received data with study records, resolve queries and document common variable definitions, units, derivations and missingness without concealing incompatible measurements.

Appraise

Choose design-appropriate appraisal methods, record the tool version and assess relevant results with supporting evidence. Resolve judgments and use them in interpretation and sensitivity analyses.

Synthesize

Apply the prespecified synthesis strategy with documented deviations. Check compatibility, dependence and uncertainty; use structured synthesis when the intended pooling is not defensible.

Assess robustness

Examine justified alternative assumptions and missing evidence. Assess certainty or confidence for the relevant outcome or comparison, explaining every judgment rather than deriving it from a single test.

Report

Report methods, deviations, selection, findings and limitations using the relevant reporting guidance. Separate planned table shells from verified results and archive reproducible materials where permitted.