Optimal Allocation of Sample Sizes to Multicenter Clinical Trials

Abstract

In this article, we discuss an approach for optimal sample size allocation in designing multicenter clinical trials. The method we studied was adapted from a stratified sampling survey design. The sample size allocated to centers is a function of the center's treatment cost, the standard deviation of the endpoint, and the availability of patients. We illustrate our approach using two hypothetical scenarios derived from our experiences in designing and conducting multicenter clinical trials. Simulation results are also presented.

Key Words:

• Cost Constraints
• Multicenter Clinical Trials
• Optimal Allocation
• Sample Size
• Weighting

ACKNOWLEDGMENTS

We acknowledge partial support provided by the Biostatistics/Epidemiology/ Research Design (BERD) Core of the Center for Clinical and Translational Sciences (CCTS) for this project. CCTS is mainly funded by NIH CTSA grant (UL1 RR024148), awarded to the UTHSC–Houston in 2006 and its renewal (UL1 TR000371) by the National Center for Advancing Translational Sciences (NCATS).