Tests of proportional hazards and proportional odds models for grouped survival data

In this paper, we derive score test statistics to discriminate between prop ortional hazards and proportional odds models for grouped survival data. Th ese models are embedded within a power family transformation in order to ob tain the score tests. In simple cases, some small-sample results are obtain ed for the score statistics using Monte Carlo simulations. Score statistics have distributions well approximated by the chi-squared distribution. Real examples illustrate the proposed tests.