ABSTRACT
There are two-built-in SAS procedures for group sequential trial designs:
SEQDESIGN procedure and SEQTEST procedure. The SEQDESIGN pro-
cedure is used to compute the boundary values and required sample sizes
for the trial. The SEQTEST procedure is used for monitoring the trial
or making decisions at the interim analyses. The SEQTEST procedure is
also used for the final analyses to compute parameter estimates, confidence
limits, and p-values after the trial stops. Our focus will be on SEQDESIGN
procedure not SEQTEST procedure.
