Graphical models and computerized adaptive testing

Computerized adaptive testing (CAT) based on item response theory (IRT) is viewed from the perspective of graphical modeling (GM). GM provides methods for making inferences about multifaceted skills and knowledge, and for extracting data from complex performances. However, simply incorporating variables for all sources of variation is rarely successful. Thus, researchers must closely analyze the substance and structure of the problem to create more effective models. Researchers regularly employ sophisticated strategies to handle many sources of variability outside the IRT model. Relevant variables can play many roles without appearing in the operational IRT model per se, e.g., in validity studies, assembling tests, and constructing and modeling tasks. Some of these techniques are described from a GM perspective, as well as how to extend them to more complex assessment situations. Issues are illustrated in the context of language testing.