Andrew Izsak

University of Georgia (UGA)

This project is developing and evaluating a test form that diagnoses teachers' capacities in two closely connected cases of reasoning about multiplicative relations among quantities: fractions and proportions. Teachers' responses to test items will be informative about their capacities to reason about content in ways that support student’s thinking. The project is developing instruments using a new class of psychometric models called Diagnostic Classifcation Models (DCMs) that are based on categorical latent variables.