Dissertation/Thesis Abstract

Performance evaluation in Bayesian adaptive randomization
by Wang, Degang, M.S., The University of Texas School of Public Health, 2008, 60; 1460814
Abstract (Summary)

Bayesian adaptive randomization (BAR) is an attractive approach to allocate more patients to the putatively superior arm based on the interim data while maintains good statistical properties attributed to randomization. Under this approach, patients are adaptively assigned to a treatment group based on the probability that the treatment is better. The basic randomization scheme can be modified by introducing a tuning parameter, replacing the posterior estimated response probability, setting a boundary to randomization probabilities. Under randomization settings comprised of the above modifications, operating characteristics, including type I error, power, sample size, imbalance of sample size, interim success rate, and overall success rate, were evaluated through simulation. All randomization settings have low and comparable type I errors. Increasing tuning parameter decreases power, but increases imbalance of sample size and interim success rate. Compared with settings using the posterior probability, settings using the estimated response rates have higher power and overall success rate, but less imbalance of sample size and lower interim success rate. Bounded settings have higher power but less imbalance of sample size than unbounded settings. All settings have better performance in the Bayesian design than in the frequentist design. This simulation study provided practical guidance on the choice of how to implement the adaptive design.

Indexing (document details)
Advisor: Lee, Jack J., Fu, Yunxin
Commitee: Boerwinkle, Eric A., Lai, Dajian
School: The University of Texas School of Public Health
Department: Biostatistics
School Location: United States -- Texas
Source: MAI 47/03M, Masters Abstracts International
Source Type: DISSERTATION
Subjects: Biostatistics, Statistics
Keywords: Adaptive randomization, Bayesian, Clinical trials
Publication Number: 1460814
ISBN: 9780549948353
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