extended · article · 1988

Measuring Attitudes With a Threshold Model Drawing on a Traditional Scaling Concept

Jürgen Rost

This paper presents a generalized Rasch model for measuring attitudes which is based on the concepts of Thurstone's method of successive intervals. The model combines the rating scale and the dispersion model proposed by Andrich and a submodel of the partial credit model proposed by Masters. An estimation pro cedure for unconditional maximum likelihood (ML) es timates is outlined. A recursion formula for the sym metric functions, which is needed for conditional ML procedures, is given. The benefits of the model are il lustrated with a study on students' interest in physics. The fit of different threshold models can be compared using conditional likelihood values and conditional likelihood ratio tests. Index terms: attitude measure ment, conditional likelihood ratio test, partial credit model, Rasch model, rating scales, successive inter vals, threshold model.