Tail Ordering and Asymptotic Efficiency of Rank Tests

Abstract

In this paper we consider a partial ordering that is "between" the stochastic ordering defined by Lehmann (1955) and an ordering associated with the monotone likelihood ratio property. A tail ordering deduced from it is applied to the comparison of the asymptotic efficiencies of rank tests in the two-sample problem. In particular, we show that the asymptotic relative efficiency of two rank tests preserve this tail ordering if one score function is "more convex" than the other.