Is. Chang et al., A CLASS OF EFFICIENT NONPARAMETRIC K-SAMPLE TESTS FOR MULTIVARIATE COUNTING-PROCESSES WITH FRAILTIES, Scandinavian journal of statistics, 25(1), 1998, pp. 127-141
A K-sample testing problem is studied for multivariate counting profes
ses with time-dependent frailty. Asymptotic distributions and efficien
cy of a class of non-parametric test statistics are established for ce
rtain local alternatives. The concept of efficiency is to show that fo
r every non-parametric test in this class, there is a parametric submo
del for which the optimal test has the same asymptotic power as the no
n-parametric one. The theory is applied to analyse a diabetic retinopa
thy study data set. A simulation study is also presented to illustrate
the theory.