For the c-sample location problem with ordered alternatives the test of Jon
ckheere (1954) and Terpstra (1952) is a well-known competitor to the parame
tric test introduced by Barlow et al. (1972, p. 184). Generalizations of th
e Jonckheere-Terpstra test are proposed e.g., by Purl (1965), Tryon and Het
tmansperger (1973) and Buning and Kossler (1996). All these tests are based
on the pairwise ranking method. In the present paper their efficacies are
compared. The Jonckheere-type and Tryon-Hettmansperger-type test statistics
can be further generalized by introducing weight coefficients to the subst
atistics. For the case of a specified alternative these weights are determi
ned to obtain maximal efficacies. It is shown that the maximal achievable e
fficacies in the defined classes of generalized Jonckheere-type tests and T
ryon-Hettmansperger-type tests always are equal.