Yongdong Ouyang

May 29, 2024 | journals.sagepub.com | Yongdong Ouyang |Monica Taljaard |Andrew Forbes |Fan Li

1 IntroductionThe cluster randomized trial (CRT) is a commonly used design for evaluating the effectiveness of cluster-level interventions or when there are substantial risks of contamination of the intervention within clusters.1 In CRTs, individuals who are members of the same group (such as a neighborhood, hospital, or school) are randomized as an entire unit to either the control or the intervention arms.