OpenBUGS for the Two- and Three-Parameter Logistic Models in Item Response Theory

• In Event: Poster Session 10
  In Poster Session: Diverse Topics in Psychometrics and Educational Measurement

Abstract

Markov chain Monte Carlo (MCMC) has been widely studied for IRT models over the past decade and a half. However, most of this research has been carried out by the researcher coding up the MCMC algorithm themselves or not specifying how they obtained the sample. OpenBUGS is a free, widely available and flexible MCMC software package that precludes the need to code the algorithm. The goal of this research is to provide practical guidelines for the use of OpenBUGS for the 2 and PL models, including script code and the importance of re-centering and scaling the ability distribution at each iterate. Hopefully, this will make MCMC more easily accessible to the IRT practitioner.

Authors

• Leslie A. Hendrix, University of South Carolina

• Brian T. Habing, University of South Carolina