There are two currently popular statistical frameworks for addressing measurement problems such as test development, test-score equating, and the identification of biased test items: classical test theory and item response theory (lRT). In this module, both theories and models associated with each are described and compared, and the ways in which test development generally proceeds within each framework are discussed. The intent of this module is to provide a nontechnical comparison of classical test theory and item response theory.

Keywords: classical test theory, CTT, item response theory, IRT, models, parameters, statistical framework