A comprehensive open-source library for exact required sample size in binary clinical trials

Abstract

We describe how we are creating a new and comprehensive R library solving the problem of exact sample size determination of RCTs. A crucial prerequisite for the trial protocol is a priori sample sizes that bound the test size below a target (often 5%) and the test power above a target (often 80%). Approximate formulas are available for binary trials but the target test size and power are often violated by standard methods for even quite large sample sizes. Moreover, adjusting standard tests to take account of their size bias can reduce power substantially. This has been well known for several decades. Exact and quasi-exact tests are now available and can be computed in a few seconds for a si..