title: Optimization of multistage testing times and critical values in clinical trials.
abstract: Optimal critical values and times of intermediate testing points are determined to minimize expected sample size in a variety of situations. Two-stage and three-stage models are considered for a variety of values of power. We investigate the robustness of the optimality parameters.
authors.affiliation: Biostatistics Research Branch, NHLBI, Bethesda, Maryland 20892.
authors.forename: E H
authors.initials: EH
authors.lastname: Brittain
authors.forename: K R
authors.initials: KR
authors.lastname: Bailey
mesh_terms: D001699:Biometry / Q000379:methods*; D001794:Blood Pressure / Q000187:drug effects; D002986:Clinical Trials as Topic / Q000379:methods* / Q000706:statistics & numerical data; D005069:Evaluation Studies as Topic; D006801:Humans; D015233:Models, Statistical; D012494:Sampling Studies; D013997:Time Factors