ABSTRACT
In this chapter, four IRT applications are illustrated. The first application is for data that consist of both dichotomous and polytomous item responses together. This mixed format response data may result from a psychological test that consists of both yes/no questions and Likert style items. Another example of mixed format data is responses collected from a cognitive test that includes dichotomously scored multiple-choice or true/false items together with constructed-response items scored based on a standardized polytomous scoring rubric.
