In this article we propose a model-free diagnostic for single-peakedness (unimodality) of item responses. Presuming a unidimensional unfolding scale and a given item ordering, we approximate item response functions of all items based on ordered conditional means (OCM). The proposed OCM methodology is based on Thurstone & Chave's (1929) "criterion…

This article proposes and describes factor-analytic procedures for assessing and controlling socially desirable responding in binary personality items. The basic procedures are applications of the restricted (confirmatory) item factor analysis model for ordered-categorical variables. Orthogonal and oblique solutions based on marker variables are…

A method for examining invariance in validity of multiple-component instruments in repeated measure designs is outlined. The approach is developed within the framework of covariance structure modeling and is applicable for purposes of ascertaining temporal stability in scale validity. In addition, the procedure provides a range of plausible values…