This National Council on Measurement in Education (NCME) instructional module compares classical test theory and item response theory and describes their applications in test development. Related concepts, models, and methods are explored; and advantages and disadvantages of each framework are reviewed. (SLD)

This instructional module discusses the one-, two-, and three-parameter logistic item response theory (IRT) models. Mathematical formulas are given for each model and they are compared, with figures illustrating the effects of changing parameters. A single data set is used to demonstrate the effects of changing parameter values. (SLD)

This article presents a model that can be used by local school districts for reanalyzing standardized test results to obtain a more valid assessment of local learning objectives can be used to identify strengths/weaknesses of existing programs as well as individual students. (EGS)