The Fusion Model Skills Diagnosis System

There is a long history of calls for combining cognitive science and psychometrics (Cronbach, 1975; Snow & Lohman, 1989). The U.S. standards movement, begun more than 20 years ago (McKnight et al., 1987; National Council of Teachers of Mathematics, 1989), sought to articulate public standards for learning that would define and promote successful performance by all students; establish a common base for curriculum development and instructional practice; and provide a foundation for measuring progress for students, teachers and programs. The standards movement provided the first widespread call for assessment systems that directly support learning. For success, such systems must satisfy a number of conditions having to do with cognitive-science–based design, psychometrics, and implementation. This chapter focuses on the psychometric aspects of one particular system that builds on a carefully designed test and a user-selected set of relevant skills measured by that test to assess student mastery of each of the chosen skills. This type of test-based skills level assessment is called skills diagnosis. The system that the chapter describes in detail is called the Fusion Model system. This chapter focuses on the statistical and psychometric aspects of the Fusion Model system, with skills diagnosis researchers and practitioners in mind who may be interested in working with this system. We view the statistical and psychometric aspects as situated within a comprehensive framework for diagnostic assessment test design and implementation. We use the term “skills diagnostic tests” to refer to tests that provide profiles of information on examinees: information