Sequential tests for clinical trials of two treatments with bounded deficiency.

In a clinical trial of two treatments, one goal of the experimenter is to design an experiment such that the number of patients assigned to the inferior treatment is minimized. A Bayesian formulation for this problem is studied. Treatment outcomes are assumed to be independent and normally distributed, with conjugate priors. The analysis is conducted in a large sample limit where sampling costs are scaled to zero. First we show there is little harm restricting attention to procedures that stop according to Kiefer and Sacks stopping rule. There are procedures in this class with risks that exceed the minimum Bayes risk by the cost of a fixed number of observations. Using this we then develop procedures with bounded deficiency. A Monte Carlo study shows that these procedures perform better than the pairwise procedure.PhDPure SciencesStatisticsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/128296/2/8907179.pd