Computational Strategies and Estimation Performance With Bayesian Semiparametric Item Response Theory Models

• Published in: Journal of educational and behavioral statistics Vol. 48; no. 2; pp. 147 - 188
• Main Authors: Paganin, Sally, Paciorek, Christopher J., Wehrhahn, Claudia, Rodríguez, Abel, Rabe-Hesketh, Sophia, de Valpine, Perry
• Format: Journal Article
• Language: English
• Published: Los Angeles, CA SAGE Publications 01.04.2023; American Educational Research Association
• Subjects: Algorithms; Bayesian analysis; Bayesian Statistics; Computer Software; Dirichlet problem; Educational tests & measurements; Evaluation Methods; Guidance; Item Response Theory; Sampling; Software; Dirichlet process mixture; MCMC strategies; binary IRT models; NIMBLE
• ISSN: 1076-9986; 1935-1054
• DOI: 10.3102/10769986221136105

Item response theory (IRT) models typically rely on a normality assumption for subject-specific latent traits, which is often unrealistic in practice. Semiparametric extensions based on Dirichlet process mixtures (DPMs) offer a more flexible representation of the unknown distribution of the latent trait. However, the use of such models in the IRT literature has been extremely limited, in good part because of the lack of comprehensive studies and accessible software tools. This article provides guidance for practitioners on semiparametric IRT models and their implementation. In particular, we rely on NIMBLE, a flexible software system for hierarchical models that enables the use of DPMs. We highlight efficient sampling strategies for model estimation and compare inferential results under parametric and semiparametric models.