Cognitive Diagnostic Computerized Adaptive Testing for Polytomously Scored Items

Abstract

Cognitive diagnostic computerized adaptive testing (CD-CAT) purports to combine the strengths of both CAT and cognitive diagnosis. Currently, large number of CD-CAT researches focus on the dichotomous data. In our knowledge, there are no researches on CD-CAT for polytomously scored items or data. However, polytomously scored items have been broadly used in a variety of tests for their advantages of providing more information about examinee, and fewer polytomous items can achieve the same precision compared with dichotomous items. Therefore, it is an interesting topic on CD-CAT with polytomously scored items, which need promote the research in polytomous cognitive diagnostic computerized adaptive testing (called PCD-CAT). This study aims to construct a framework of PCD-CAT, including the construction of the item bank, the item selection method, the parameter estimation, and the termination rule.