Based on a tremendous increase in the development of psychometric theories in the past decade -- ranging from techniques for criterion-referenced testing to behavioral assessment, generalizability, and item response theory -- this book offers a summary of core issues. In so doing, it provides a comprehensive survey of reliability, validity, and item analysis from the perspectives of classical true-score model, generalizability theory, item response theory, criterion-referenced testing, and behavioral assessment. Related theoretical issues such as item bias, equating, and cut-score determination are also discussed. This is an excellent text for courses in statistics, research methods, behavioral medicine and cognitive science as well as educational, school, experimental, counseling/social, clinical, developmental, and personality psychology.