A simple method of sample size calculation for unequal-sample-size designs that use the logrank or t-test.

This paper presents a simple method of calculating sample sizes for unequal-sample-size designs with use of published tables applicable to equal-sample-size design. The method applies to both the logrank test and the t-test. For the power of logrank test, this paper compares the proposed method with existing methods and with the Monte Carlo simulation.