Pairwise multiple comparison test procedures: an update for clinical child and adolescent psychologists.

Locating pairwise differences among treatment groups is a common practice of applied researchers. Articles published in this journal have addressed the issue of statistical inference within the context of an analysis of variance (ANOVA) framework, describing procedures for comparing means, among other issues. In particular, 1 article (Jaccard & Guilamo-Ramos, 2002b) presented some new methods of performing contrasts of means whereas another presented a framework for obtaining robust tests within this same context (Jaccard & Guilamo-Ramos, 2002a). The purpose of this article is to add to these contributions by presenting some newer methods for conducting pairwise comparisons of means, that is by extending the contributions of the first article and applying the framework of the second article to pairwise multiple comparisons. The newer methods are intended to provide additional sensitivity to detect treatment group differences and provide tests that are robust to the effects of variance heterogeneity, nonnormality, or both.