Power and Sample Size with spower from Hmisc

We simulate a 2-arm 5-year follow-up study using Hmisc. All subjects are followed at least one year, and patients enter the study with linearly increasing probability starting with zero. Assume (1) there is no chance of dropin for the first 6 months, then the probability increases linearly up to .15 at 5 years; and (2) there is a linearly increasing chance of dropout up to .3 at 5 years.

Instructions

• Click on the Design Displays and Results tabs above to see graphics and spower results.
• Change any variable on the left and it will automatically update the tabs.