Analysis of variance for repeated measures designs with word materials as a nested random or fixed factor

This article is about analysis of data obtained in repeated measures designs in psycholinguistics and related disciplines with items (words) nested within treatment (= type of words). Statistics tested in a series of computer simulations are: F1, F2, F1 & F2, F', min F', plus two decision procedures, the one suggested by Forster and Dickinson (1976) and one suggested by the authors of this article. The most common test statistic, F1 & F2, turns out to be wrong, but all alternative statistics suggested in the literature have problems too. The two decision procedures perform much better, especially the new one, because it systematically takes into account the subject by treatment interaction and the degree of word variability.