ABSTRACT
There are a variety of published educational tests that include the label diagnostic in their titles or that purport to provide instructionally useful diagnostic information. Most of them, however, differ considerably from the type of diagnostic testing that was described in the three preceding chapters by Embretson, Marshall, and Tatsuoka. For example, published diagnostic tests are often used to classify students rather than to prescribe specific instructional activities. They generally lack a clearly articulated analysis of the tasks or a representation of the cognitive skills that the items are intended to measure. Finally, if they are based on psychometric theory at all, they rely on models that were developed for other purposes.
