Compute Drift Given Power and Bounds

This program computes drift given power and bounds.  It is based upon the Lan-DeMets method, and allows computation of boundaries at any time during the monitoring of a study. It is valid for any normal test statistic with independent increments. The information time is the ratio of accrued sample size to the total sample size for normal data.

Number of interim analyses
Equally spaced times between 0 and 1 Yes   No
Information Times: (>0 & <=1)
Overall significance level? (>0 and <=1)
One, two-sided symmetric or asymmetric? One   Two  Asymmetric
Type of spending function
Do you wish to truncate the standardized bounds? Yes   No
Desired power

Main Page | Questions/Comments |