Item Response Theory (IRT) Models for Dichotomous Data

This entry provides an introduction to the topic of item response theory. Shortcomings of classical test models are considered first. Second, current item response models for the analysis of dichotomously scored item response data are introduced. Estimation of model parameters, assessment of model fit, and available software, are described next. Finally, applications of item response theory IRT models to test development, item bias, equating, and computer-adaptive testing are briefly described. Keywords: item response theory; latent trait theory; item characteristic functions; test characteristic functions; item and test information functions; test development; identification of item bias; test score equating; computer-adaptive testing