Mokken scale analysis for polychotomous items: theory, a computer program and an empirical application

An extension of Mokken's nonparametric item response models from dichotomous items to items with two or more ordered answer categories is proposed and a computer program to analyze multicategory item scores is presented.

Abstract

This paper contains three subjects. First, an extension of Mokken's nonparametric item response models from dichotomous items to items with two or more ordered answer categories is proposed. Second, a computer program to analyze multicategory item scores is presented. This program is called MSP. The analyses by means of MSP are based on the multicategory extension of Mokken's theory. Finally, an application of MSP to empirical multicategorytest data is presented in order to illuminate its possibilities.