title: Optimal adaptive designs for binary response trials.
abstract: We derive the optimal allocation between two treatments in a clinical trial based on the following optimality criterion: for fixed variance of the test statistic, what allocation minimizes the expected number of treatment failures? A sequential design is described that leads asymptotically to the optimal allocation and is compared with the randomized play-the-winner rule, sequential Neyman allocation, and equal allocation at similar power levels. We find that the sequential procedure generally results in fewer treatment failures than the other procedures, particularly when the success probabilities of treatments are smaller.
authors.affiliation: Department of Mathematics and Statistics, University of Maryland, Baltimore County, Baltimore 21250, USA. billr@math.umbc.edu
authors.forename: W F
authors.initials: WF
authors.lastname: Rosenberger
authors.forename: N
authors.initials: N
authors.lastname: Stallard
authors.forename: A
authors.initials: A
authors.lastname: Ivanova
authors.forename: C N
authors.initials: CN
authors.lastname: Harper
authors.forename: M L
authors.initials: ML
authors.lastname: Ricks
mesh_terms: D001699:Biometry; D002986:Clinical Trials as Topic / Q000706:statistics & numerical data*; D004992:Ethics, Medical; D006801:Humans; D015233:Models, Statistical; D016032:Randomized Controlled Trials as Topic / Q000706:statistics & numerical data; D017211:Treatment Failure