Multidimensional Item Response Theory and the BEMA: Modeling Student Thinking

Abstract

This study applies Multidimensional Item Response Theory (MIRT) analysis using confirmatory methods to the Brief Electricity and Magnetism Assessment (BEMA) to explore the assessment's structure and to determine an optimal model of student knowledge measured by the assessment. These methods were used to investigate a large dataset (N=9666) from a research university in the western United States. Confirmatory MIRT analysis fit a theoretical model developed from expert solutions to the instrument and identified two optimal models: an optimal principle model and an optimal topical model. The optimal principle model consisted of 28 principles, fundamental reasoning steps needed to solve items in the BEMA. A second model, the optimal topical model, consisted of five general subtopics of electromagnetism. Both the optimal principle and optimal topical model had excellent fit statistics.