• cognitive models;
  • construct validity;
  • diagnostic testing;
  • educational measurement

The purpose of this paper is to define and evaluate the categories of cognitive models underlying at least three types of educational tests. We argue that while all educational tests may be based—explicitly or implicitly—on a cognitive model, the categories of cognitive models underlying tests often range in their development and in the psychological evidence gathered to support their value. For researchers and practitioners, awareness of different cognitive models may facilitate the evaluation of educational measures for the purpose of generating diagnostic inferences, especially about examinees' thinking processes, including misconceptions, strengths, and/or abilities. We think a discussion of the types of cognitive models underlying educational measures is useful not only for taxonomic ends, but also for becoming increasingly aware of evidentiary claims in educational assessment and for promoting the explicit identification of cognitive models in test development. We begin our discussion by defining the term cognitive model in educational measurement. Next, we review and evaluate three categories of cognitive models that have been identified for educational testing purposes using examples from the literature. Finally, we highlight the practical implications of “blending” models for the purpose of improving educational measures.