The second edition of the only practical guide for clinicians developing tools to measure subjective states, attitudes, and other 'non-tangible' outcomes in their patients has been thoroughly revised to incorporate all the latest research results. New to this edition are a chapter on ethics and a discussion of reliability and generalizability theory. The authors offer an overview of both the theory and the practical applications of health measurement scales, and offer the reader a methodical, step-by-step guidance to the development of their own scales. These features combine to provide the most up-to-date guide to measurement scale development available. Written in a concise and intelligible style, it enables both experienced researchers and novices to develop accurate, sensitive and easy-to-use measurement scales of their own. This is an essential book for anyone who uses or would like to use rating scales in their clinical practice.