Appendix H. Finding Adjusted Alphas for Interim Analyses−SAS Examples
H.1 Introduction 499
H.2 Pocock's Approach 499
H.3 O'Brien-Flemming Approach 501
H.4 Lan-DeMets Cumulative α-Spending Function 503
H.5 Lan-DeMets α-Spending Function 506
Beginning with SAS 9.2, the procedures SEQDESIGN and SEQTEST can be used to help design and analyze interim clinical investigations. In the examples discussed in Section 2.6, you may use PROC SEQDESIGN to obtain the adjusted alphas by using the appropriate options and parameters. You may also obtain the stopping boundaries using the same procedure. The SEQTEST procedure is used in conjunction with SEQDESIGN to conduct the testing at the interim stages. Normally, the statistician uses PROC SEQDESIGN ...