Abstract:
:Adaptive designs have been proposed for clinical trials in which the nuisance parameters or alternative of interest are unknown or likely to be misspecified before the trial. Although most previous works on adaptive designs and mid-course sample size re-estimation have focused on two-stage or group-sequential designs in the normal case, we consider here a new approach that involves at most three stages and is developed in the general framework of multiparameter exponential families. This approach not only maintains the prescribed type I error probability but also provides a simple but asymptotically efficient sequential test whose finite-sample performance, measured in terms of the expected sample size and power functions, is shown to be comparable to the optimal sequential design, determined by dynamic programming, in the simplified normal mean case with known variance and prespecified alternative, and superior to the existing two-stage designs and also to adaptive group-sequential designs when the alternative or nuisance parameters are unknown or misspecified.
journal_name
Stat Medjournal_title
Statistics in medicineauthors
Bartroff J,Lai TLdoi
10.1002/sim.3201subject
Has Abstractpub_date
2008-05-10 00:00:00pages
1593-611issue
10eissn
0277-6715issn
1097-0258journal_volume
27pub_type
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