The Rasch model as additive conjoint measurement

Abstract

The object of this paper is to present Rasch’s psychometric model as a special case of additive conjoint measurement. The connection between these two areas has been discussed before, but largely ignored. Because the theory of conjoint measurement has been formulated deterministically, there have been some difficulties in its application. It is pointed out in this paper that the Rasch model, which is a stochastic model, does not suffer from this fault. The exposition centers on the analyses of two data sets, each of which was analyzed using Rasch scaling methods as well as some of the methods of conjoint measurement. The results, using the different procedures, are compared.