Unified Cognitive/Psychometric Diagnostic Assessment Likelihood-Based Classification Techniques: Louis V. DiBello, William F. Stout, and Louis A. Roussos
Paul D. Nichols, Susan F. Chipman, Robert L. Brennan · 2012
A new psychometric approach to cognitive diagnostic assessment was proposed by DiBello, Stout, and Roussos (1993). They developed a new item response model, called the unified model, that brings together the discrete, deterministic aspects of cognition favored by cognitive scientists, and the continuous, stochastic aspects of test response behavior that underlie item response theory. The goal is to be able to determine, on the basis of a simple test, what the cognitive strengths and weaknesses of an examinee are, relative to a specified list of cognitive attributes of interest to the teacher and the tester. For example, one may be interested in using cognitive information about students for instructional assignment. Standard multidimensional item response theory fails to do this. There is an important need for a test analysis method that extracts from ordinary tests cognitive information that is useful to the practitioner. Such methods and underlying theory should be applicable to tests that are in common use today, such as teacher-made classroom tests, nationally administered standardized subtests such as the Armed Services Vocational Aptitude Battery Autoshop test or the Law School Admissions Test of Analytical Reasoning, and certification tests such as those administered by the National Council of State Boards of Nursing, as well as to specially constructed diagnostic instruments that are based on cognitive theory. The unified model blends psychometric and cognitive science viewpoints and promises to allow the practitioner to recover cognitive information from simple, well-designed tests. In this chapter, we discuss current attempts to bring together cognitive science and psychometrics, review the unified model and likelihood-based diagnostic classification techniques based on it, and summarize the results of a simulation study.