November 21, 2023
IMPACT Design and Statistics core members, Fan Li, PhD, Kendra Plourde, PhD, and Monica Taljaard, PhD, are among authors reviewing stepped-wedge cluster randomized trials (SW-CRT) from 2016 to 2022 to understand how well the studies adhered to design and analysis recommendations. SW-CRT is an increasingly popular design for evaluating health service delivery or policy interventions. The team looked at 160 trials with complex design features. The authors conclude that researchers and trial publishers should be aware of additional requirements for SW-CRT’s.
Abstract:
The stepped-wedge cluster randomized trial (SW-CRT), in which clusters are randomized to a time at which they will transition to the intervention condition – rather than a trial arm – is a relatively new design. SW-CRTs have additional design and analytical considerations compared to conventional parallel arm trials. To inform future methodological development, including guidance for trialists and the selection of parameters for statistical simulation studies, we conducted a review of recently published SW-CRTs. Specific objectives were to describe (1) the types of designs used in practice, (2) adherence to key requirements for statistical analysis, and (3) practices around covariate adjustment. We also examined changes in adherence over time and by journal impact factor.