Empirical power and sample size calculations for cluster-randomized and cluster-randomized crossover studies
Nicholas G Reich, Jessica A Myers, Daniel Obeng, Aaron M Milstone, Trish M Perl, Nicholas G Reich, Jessica A Myers, Daniel Obeng, Aaron M Milstone, Trish M Perl
Abstract
In recent years, the number of studies using a cluster-randomized design has grown dramatically. In addition, the cluster-randomized crossover design has been touted as a methodological advance that can increase efficiency of cluster-randomized studies in certain situations. While the cluster-randomized crossover trial has become a popular tool, standards of design, analysis, reporting and implementation have not been established for this emergent design. We address one particular aspect of cluster-randomized and cluster-randomized crossover trial design: estimating statistical power. We present a general framework for estimating power via simulation in cluster-randomized studies with or without one or more crossover periods. We have implemented this framework in the clusterPower software package for R, freely available online from the Comprehensive R Archive Network. Our simulation framework is easy to implement and users may customize the methods used for data analysis. We give four examples of using the software in practice. The clusterPower package could play an important role in the design of future cluster-randomized and cluster-randomized crossover studies. This work is the first to establish a universal method for calculating power for both cluster-randomized and cluster-randomized clinical trials. More research is needed to develop standardized and recommended methodology for cluster-randomized crossover studies.
Trial registration: ClinicalTrials.gov NCT01249625.
Conflict of interest statement
Competing Interests: This study was partly funded by Sage Products, Inc. There are no patents, products in development or marketed products to declare. This does not alter the authors’ adherence to all the PLoS ONE policies on sharing data and materials.
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Source: PubMed