The increased awareness of the impact of health care on the quality of human life means that clinical researchers working in a wide spectrum of disciplines need information about measures such as pain, depression, or function. A sound, scientific and reproduceable system of measurement is required by researchers in disciplines such as psychiatry, rheumatology, oncology - and other health professions such as nursing, physiotherapy, and occupational therapy. Based on a graduate course developed by the authors at McMaster University, this book introduces concepts of measurement to researchers in health sciences, emphasizing applications rather than theory. Topics are covered in the order they might confront someone faced with the problem of developing a new measurement, beginning with an overview of the criteria which should be used to assess any measurement instrument. Finally, appendices show the reader how to find further information about tests and scales.