title: Adaptive statistical analysis following sample size modification based on interim review of effect size.
abstract: In designing a comparative clinical trial, the required sample size is a function of the effect size, the value of which is unknown and at best may be estimated from historical data. Insufficiency in sample size as a result of overestimating the effect size can be destructive to the success of the clinical trial. Sample size re-estimation may need to be properly considered as a part of clinical trial planning. This paper is intended to give the motivations for the sample size re-estimation based partly on the effect size observed at an interim analysis and for a resulting simple adaptive test strategy. The performance of this adaptive design strategy is assessed by comparing it with a fixed maximum sample size design that is properly adjusted in anticipation of the possible sample size adjustment.
authors: Division of Biometrics I, OB/OPaSS/CDER, FDA, Rockville, Maryland, USA. hung@cder.fda.gov
authors: H M James
authors: HM
authors: Hung
authors: Lu
authors: L
authors: Cui
authors: Sue-Jane
authors: SJ
authors: Wang
authors: John
authors: J
authors: Lawrence
mesh_terms: D000465:Algorithms; D002986:Clinical Trials as Topic / Q000706:statistics & numerical data; D003627:Data Interpretation, Statistical; D012107:Research Design / Q000706:statistics & numerical data*; D018401:Sample Size