Data Analysis Papers
Group Sequential Analysis Using the New SEQDESIGN and SEQTEST Procedures
Yuan, Yang C.; SAS Institute 2009
Abstract
In a fixed-sample clinical trial, data on all individuals are analyzed at the end of the study. In contrast, a group sequential trial provides for interim analyses before completion of the trial. Thus, a group sequential trial is useful for preventing unnecessary exposure of patients to an unsafe new drug or to a placebo treatment if a new drug shows significant improvement.
This paper reviews basic concepts of group sequential analysis and introduces two SAS/STAT® procedures: the SEQDESIGN and SEQTEST procedures. Both procedures are experimental in SAS® 9.2. The SEQDESIGN procedure creates group sequential designs by computing boundary values with a variety of methods, including the O’Brien-Fleming, Whitehead, and error spending methods; it also provides required sample sizes. The SEQTEST procedure compares the test statistic with the boundary values at each stage so that the trial can be stopped to reject or accept the hypothesis; it also computes parameter estimates, confidence limits, and p-values after the trial stops.
Statistics and Operations
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