This book applies the principles of measurement developed in education and psychology to the health sciences. It answers the need for a sound, reproducible system of assessment techniques that can be applied in fields ranging from psychiatry to oncology, where clinical researchers are called on to measure pain, depression, function and other "quality-of-life" variables. Logically arranged and easily comprehensible, this "hands-on" guide emphasizes practical applications. It provides all the information needed to develop new measurement scales, from the first literature search to the design and the analysis of reliability and validity studies. Although the examples are drawn from health sciences, the book should also be useful to all students of measurement in the social and behavioral sciences.