A Note on Knowledge-Based Model Construction in Educational Assessment

This paper discusses the concept of “conformability” between graphical model fragments used with knowledge-based model construction in educational assessment. One fragment contains the persistent student model, or variables which are the primary targets of inference. Fragments corresponding to tasks contain one or more observable variables, which are children of one or more student model variables. These latter evidence models are attached to the student model, evidence is absorbed as observations are made, and the fragment is released. The consideration addressed here is ensuring that the boundary between the compiled student model and evidence model fragments supports coherent propagation of information. The issue is illustrated with a numerical example, and approaches for forcing comparability are suggested.