This book develops an intuitive understanding of IRT principles through the use of graphical displays and analogies to familiar psychological principles. It surveys contemporary IRT models, estimation methods, and computer programs. Polytomous IRT models are given central coverage since many psychological tests use rating scales.

Ideal for clinical, industrial, counseling, educational, and behavioral medicine professionals and students familiar with classical testing principles, exposure to material covered in first-year graduate statistics courses is helpful. All symbols and equations are thoroughly explained verbally and graphically.

Contents: Preface. Part I: Introduction. Introduction. Part II: Item Response Theory Principles: Some Contrasts and Comparisons. The New Rules of Measurement. Item Response Theory as Model-Based Measurement. Part III: The Fundamentals of Item Response Theory. Binary IRT Models. Polytomous IRT Models. The Trait Level Measurement Scale: Meaning, Interpretations, and Measurement-Scale Properties. Measuring Persons: Scoring Examinees With IRT Models. Calibrating Items: Estimation. Assessing the Fit of IRT Models. Part IV: Applications of IRT Models. IRT Applications: DIF, CAT, and Scale Analysis. IRT Applications in Cognitive and Developmental Assessment. Applications of IRT in Personality and Attitude Assessment. Computer Programs for Conducting IRT Parameter Estimation.

Susan E. Embretson Georgia Institute of Technology, Atlanta, USA. Steven P. Reise University of California, Losa Angeles, USA