The stepped-wedge (SW) cluster-randomized trial design is particularly suitable for, and has been frequently adopted for, pragmatic clinical trials. Initially, all clusters receive control treatment. Subsequently, at predefined steps, clusters are randomized to switch to intervention. Outcomes are measured at every step. All participants receive the intervention at the end of the study. An SW trial is advantageous in eliminating the ethical dilemma of withholding an effective treatment (for closed-cohort trials); is logistically more manageable due to stepwise switchover from control to intervention; and, because it is based on longitudinal measurements, is informative about the trend in treatment effect.
