For comparison of multiple groups to a single control for a nonparametric analysis (Kruskal-Wallis), Dunn's test is often recommended. While also influenced by ties (as is any rank based analysis), it is not as affected as Dunnett's test. SAS does not currently offer Dunn's as a multiplicity adjustment, so you would probably have to search for it on the internet.
However, SAS does offer the method of Edwards and Berry (ADJUST=SIMULATE), which is truly distribution-free, and provides superior family-wise error control to any of the other methods available for the LSMEANS or LSMESTIMATE statement.
SteveDenham
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