Design Issues for Randomized Trials

Abstract

In this chapter, we consider issues involved when designing studies with time-to-event outcomes. This includes determining the expected number of events to occur over the study period, the total number of subjects to be recruited into the study, the power of the study, the time period over which to accrue the study subjects, the time period over which enrolled subjects will be followed, and how to adjust sample size requirements to allow for subjects who might be lost to follow-up and/or who might switch therapies from the one they were originally allocated during the study period.