Publications & Resources
Semi-Parametric Item Response Functions in the Context of Guessing
Carl F. Falk and Li Cai
We present a logistic function of a monotonic polynomial with a lower asymptote, allowing additional flexibility beyond the three-parameter logistic model. We develop a maximum marginal likelihood based approach to estimate the item parameters. The new item response model is demonstrated on math assessment data from a state, and a computationally efficient strategy for choosing the order of the polynomial is demonstrated and tested.
Falk, C. F., & Cai, L. (2015). Semi-parametric item response functions in the context of guessing (CRESST Report 844). Los Angeles: University of California, Los Angeles, National Center for Research on Evaluation, Standards, and Student Testing (CRESST).