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Activity Number: 324 - Causal Inference, Empirical Bayes and Related Topics in Regression
Type: Contributed
Date/Time: Wednesday, August 5, 2020 : 10:00 AM to 2:00 PM
Sponsor: IMS
Abstract #309813
Title: Sample Size Estimation and Power Analysis in Longitudinal and Crossover Cluster Randomized Trials
Author(s): Jijia Wang*
Companies: UT Southwestern Medical Center
Keywords: Longitudinal cluster randomized trial ; Crossover cluster randomized trial ; Sample size; Power analysis; Missing data
Abstract:

Longitudinal cluster randomized trial (LCRT) and crossover cluster randomized trial (CCRT) are two variants of cluster randomized trials. In LCRTs, clusters of subjects are randomly assigned to different treatment groups and each subject has repeated measurements over the study period. In CCRTs, clusters of subjects are randomly assigned to different sequences. Within each sequence, clusters receive all treatments in a particular order. Both of LCRTs and CCRTs lead to complicated correlation structures that involve longitudinal and intracluster correlations. Generalized linear mixed model (GLMM) and generalized estimating equation (GEE) approaches have been frequently employed in data analysis and sample size estimation. In this study we propose closed-form sample size and power formulas for LCRTs and CCRTs based on the GEE approach. Those formulas are flexible to incorporate unbalanced design, different missing data patterns, and complicated correlation structures. Extensive simulation studies show that the proposed methods achieve good performance with empirical powers and type I errors close to their nominal values.


Authors who are presenting talks have a * after their name.

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