In the Introduction to this volume, we began by describing key concepts that underlie cognitive diagnostic assessment (CDA) and by specifying some of the early ideas and precedents that guided the merger between cognitive psychology and educational measurement. Then, three distinct sections were presented where a host of esteemed contributors described research on topics related to CDA, theory, and practice. Chapters describing the foundations of CDA, principles of test design and analysis, and psychometric procedures and applications were presented. After surveying these chapters, we acknowledge that not all issues relevant to CDA were adequately covered. Some omissions occurred not because these topics are considered unimportant, but because, in some cases, the topics are not ready for discussion and, in other cases, the most appropriate authors were unavailable. Thus, in the final section, we highlight some of the important topics that were not covered in this book and, in the process, identify areas in which future research is required.

ISSUE 1: ROLE OF COGNITIVE MODELS IN COGNITIVE DIAGNOSTIC ASSESSMENT

Every author in this volume claims that some type of cognitive model is required to make inferences about examinees' problem-solving skills. These models provide the framework necessary for guiding item development and directing psychometric analyses so test performance can be linked to specific inferences about examinees' cognitive skills. The foundation for generating diagnostic inferences, in fact, rest with cognitive theories and models. Hence, the veracity of the cognitive models and the validity of the diagnostic inferences must be evaluated.