ABSTRACT
This chapter presents an approach to D-scoring and analysis of polytomous items with ordered response categories (e.g., constructed response items). The procedure is based on a simple recoding of polytomous item scores into binary scores to allow for DSM-based scoring. It is shown that the results are consistent with those produced by the graded response model (GRM) in item response theory (IRT) in the sense that the ability scores under the two approaches are highly correlated, and the category response functions on the D-scale behave similarly to their GRM counterparts on the logit scale.
