Item response theory (IRT) methodology forms the foundation of many psychometric applications, including its use for equating alternate examination forms, for instrument design and development, for item banking, for computerized adaptive testing, for certification testing, and in various other psychological assessment domains. In this text, De Ayala (educational psychology, U. of Nebraska, Lincoln) provides researchers, psychometric professionals, and advanced students with a discussion of the "how to" and the "why" of IRT, by describing simple and more complex IRT models and demonstrating how they are applied with the help of widely available software packages. To facilitate understanding of the application of the models, common data sets are used across the chapters, and the terminology used is more general than is typically seen in IRT textbooks. The text assumes familiarity with common psychometric concepts, such as reliability, validity, scaling, levels of measurement, factor analysis, and regression analysis. Annotation ©2009 Book News, Inc., Portland, OR (booknews.com)