Introduction to Measurement Theory bridges the gap between texts that offer a mathematically rigorous treatment of the statistical properties of measurement and ones that discuss the topic in a basic, “cookbook” fashion. Without overwhelming novices or boring the more mathematically sophisticated, the authors effectively cover the construction of psychological tests and the interpretation of test scores and scales; critically examine classical true-score theory; and explain theoretical assumptions and modern measurement models, controversies, and developments. Practical applications, examples, and study questions facilitate a better understanding of the uses and limitations of common measures of test reliability and validity and how to perform the basic item analysis necessary for test construction.