Assessments in response formats with ordered categories are ubiquitous in the social and health sciences. Although the assumption that the ordering of the categories is working as intended is central to any interpretation that arises from such assessments, testing that this assumption is valid is not standard in psychometrics. This is surprising…

This Monte Carlo study was designed to investigate empirically the efficacy of three statistical strategies for estimating the relationships in extreme group designs in terms of estimation of correlation, power and mean square error for the correlation. Alf and Abrahams's "covariance information statistic" proved to be the best strategy.…

Six models for evaluating change are examined via a Monte Carlo study. All six models show a lack of power. A modified analysis of variance procedure is suggested as an alternative. (JKS)