This seven-part, self-paced online course from the NIH Office of Disease Prevention provides an overview of group-randomized trials (GRTs), also called cluster-randomized trials, a type of comparative studies designed to evaluate interventions that operate at a group level, change the physical or social environment, or cannot be delivered to individuals without substantial risk of contamination.
Content includes an overview of GRTs, study design, analysis approaches, power and sample size issues, and alternative designs. Prior training in basic research design and regression methods is recommended.