ABSTRACT
Item responses could be more than dichotomous outcomes. Responses for constructed-response partial credit items and Likert style responses are scored polytomously. Numbers assigned for different categorically ordered responses are typically 0,1, 2, and 3 (or 1, 2, 3 and 4) for a four-option or four-level set of categories in an item. This chapter introduces the applications of the IRT models that handle polytomously scored item responses.
