Assessing Language Skills Using Diagnostic Classification Models: An Example Using a Language Instrument.

The primary purpose of the present study is to inform and illustrate, using examples, the use of Diagnostic Classification Models (DCMs) for the assessment of skills and competencies in cognition and academic achievement. A secondary purpose is to compare and contrast traditional and contemporary psychometrics for the measurement of skills and competencies. DCMs are described along the lines of other psychometric models within the Confirmatory Factor Analysis tradition such as the bifactor model and the known mixture models that are utilized to classify individuals into subgroups. The inclusion of interaction terms and constraints along with its confirmatory nature enables DCMs to accurately assess the possession of skills and competencies. The above is illustrated using an empirical dataset from Saudi Arabia (n = 2642), in which language skills are evaluated on how they conform to known levels of competency based on the CEFR (Council of Europe, 2001) using the English Proficiency Test (EPT).