Abstract:
Cognitive diagnosis has recently gained prominence in educational assessment, psychiatric evaluation, and many other disciplines. Generally, entries in the Q-matrix of traditional cognitive diagnostic tests are binary (two levels, defined as 0 and 1). Polytomous attributes (multi-levels, defined as 0, 1, …), particularly those defined as part of the test development process, can provide additional diagnostic information. Compared to binary attributes, polytomous attributes can not only describe the student's knowledge profile, but can provide more extensive details. As we all know, Q-matrix impacts the accuracy of cognitive diagnostic assessment greatly. Research on the effect of parameter estimation and classification accuracy caused by the error in Q-matrix already existed, and it turned out that Q-matrix gotten from expert definition or experience was more easily subject to be affected by subjective factors, lead to a misspecified Q-matrix. Under this circumstance, it’s urgently needed to find more objective polytomous-attribute Q-matrix verification and inference methods. The present research proposes the verification and estimation of expert-defined polytomous attribute Q-matrix based on the polytomous deterministic inputs, noisy, ‘‘and’’ gate (p-DINA) model. We intend to extend the methods adapted to binary Q-matrix verification and estimation to polytomous attribute Q-matrix, and the proposed methods which can be used in different conditions are joint estimation and online estimation. Simulation results show that: the joint estimation algorithm can be applied to the Q-matrix validation which needs an initial Q-matrix defined by experts, the online estimation algorithm can be applied to online estimate the “new items” based on a certain number of “based items”. Under the various settings in the simulations, the two estimation algorithms can recover the correct polytomous-attribute Q-matrix at a high probability. Empirical study also indicates that the two proposed algorithms can be applied in Q-matrix validation or estimation for CDA with polytomous attributes.