Social and Behavioral Sciences Commons^™

The Effect Of Cluster Size Variability On Statistical Power In Cluster-Randomized Trials, Stephen A. Lauer, Ken P. Kleinman, Nicholas G. Reich

Biostatistics and Epidemiology Faculty Publications Series

The frequency of cluster-randomized trials (CRTs) in peer-reviewed literature has increased exponentially over the past two decades. CRTs are a valuable tool for studying interventions that cannot be effectively implemented or randomized at the individual level. However, some aspects of the design and analysis of data from CRTs are more complex than those for individually randomized controlled trials. One of the key components to designing a successful CRT is calculating the proper sample size (i.e. number of clusters) needed to attain an acceptable level of statistical power. In order to do this, a researcher must make assumptions about the value …