SEQDESIGN Procedure

The SEQDESIGN procedure designs interim analyses for clinical trials. PROC SEQDESIGN computes the boundary values and required sample sizes for the trial. The boundary values are derived in such a way that the overall Type I and Type II error probability levels are maintained at the levels specified in the design. Available methods include fixed boundary shape methods (which include unified family methods such as the O’Brien-Fleming method), Whitehead methods, and error spending methods. In addition to the boundary values, the SEQDESIGN procedure computes a variety of quantities such as average sample sizes and stopping probabilities.