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June 2008 Multi-center clinical trials: Randomization and ancillary statistics
Lu Zheng, Marvin Zelen
Ann. Appl. Stat. 2(2): 582-600 (June 2008). DOI: 10.1214/07-AOAS151


The purpose of this paper is to investigate and develop methods for analysis of multi-center randomized clinical trials which only rely on the randomization process as a basis of inference. Our motivation is prompted by the fact that most current statistical procedures used in the analysis of randomized multi-center studies are model based. The randomization feature of the trials is usually ignored. An important characteristic of model based analysis is that it is straightforward to model covariates. Nevertheless, in nearly all model based analyses, the effects due to different centers and, in general, the design of the clinical trials are ignored. An alternative to a model based analysis is to have analyses guided by the design of the trial. Our development of design based methods allows the incorporation of centers as well as other features of the trial design. The methods make use of conditioning on the ancillary statistics in the sample space generated by the randomization process. We have investigated the power of the methods and have found that, in the presence of center variation, there is a significant increase in power. The methods have been extended to group sequential trials with similar increases in power.


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Lu Zheng. Marvin Zelen. "Multi-center clinical trials: Randomization and ancillary statistics." Ann. Appl. Stat. 2 (2) 582 - 600, June 2008.


Published: June 2008
First available in Project Euclid: 3 July 2008

zbMATH: 05591289
MathSciNet: MR2524347
Digital Object Identifier: 10.1214/07-AOAS151

Keywords: design based analyses , Multi-center trials , permuted blocks design , Randomization

Rights: Copyright © 2008 Institute of Mathematical Statistics

Vol.2 • No. 2 • June 2008
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