  Item Response Theory (IRT) is a popular assessment method used in education
measurement, which builds on an assumption of a probability framework
connecting students' innate ability and their actual performances on test
items. The model transforms students' raw test scores through a nonlinear
regression process into a scaled proficiency rating, which can be used to
compare results obtained with different test questions. IRT also provides a
theoretical approach to address ceiling effect and guessing. We applied IRT to
analyze the Force Concept Inventory (FCI). The data was collected from 2802
students taking intro level mechanics courses at The Ohio State University. The
data was analyzed with a 3-parameter item response model for multiple choice
questions. We describe the procedures of the analysis and discuss the results
and the interpretations. The analysis outcomes are compiled to provide a
detailed IRT measurement metric of the FCI, which can be easily referenced and
used by teachers and researchers for a range of assessment applications.
