A two-sample censored-data rank test for acceleration.

A score test for the null hypothesis of proportional hazards against rank-regression alternatives is proposed as a complement to the logrank test for comparing censored survival curves. The test statistic has an asymptotic normal distribution that is independent of the logrank distribution under the null hypothesis, and its power is good against acceleration alternatives (i.e. with crossing hazards) where the logrank test fails. Monte Carlo studies indicate that its small-sample properties are comparable to those of the logrank and ranksum procedures.