Stepped-wedge trial overview — Stepped-wedge cluster trial

Question

Define why a randomized staged rollout can answer the intervention question.

Protocol and registration

Prespecify rollout, sampling, time effects, correlation and analysis; obtain approvals and register prospectively.

Recruit clusters

Recruit eligible clusters and define participant sampling within each calendar period.

Randomize transition sequences

Randomize clusters to transition sequences and conceal assignment where operationally possible.

Observe repeated periods

Collect outcomes in all planned cluster-periods and link repeated participants when the design follows them.

Transition interventions

Implement the assigned transitions and record delays, learning periods and changes in fidelity.

Analyze time and clustering

Separate intervention exposure from calendar time and account for multilevel dependence and exposure duration.

Report

Report the sequence-period design, denominators, deviations and time-model assumptions with stepped-wedge guidance.

Stepped-wedge trial overview

End flow

Protocol and decision register

Record the protocol, approvals and registration where applicable. Preserve planned decisions and amendments separately from results.

Protocol and rationale evidence

Attach the dated protocol, approvals and amendments. A clinical trial registry publicly records the trial plan, such as ClinicalTrials.gov or an eligible WHO primary registry such as ISRCTN. Record the registry name, identifier and registration date before first enrollment. WHO ICTRP is a search platform, not itself a registry. Registration does not imply randomization.