Sample size calculations for planning these two-stage randomized trials with failure time outcomes are challenging because the variances of common test statistics depend in a complex manner on the ...

In a non-randomized study, besides the treatment covariate, there are also other covariates that are used in a regression. The relationship between the main covariate and other covariates needs to be ...

Conclusions: The one-sample methodology accurately estimates the HR outcome of a randomized trial but, for equal sample size, underestimates the variance by approximately 25%. We propose that a ...