John Cairney & Geoffrey R. Norman 
Health Measurement Scales [PDF ebook] 
A practical guide to their development and use

Health Measurement Scales is the ultimate guide to appraising, developing, and validating measurement scales that are used in the health sciences. Written in a clear and practical style, this guide enables clinicians and researchers to both develop scales to measure subjective states and non-tangible health outcomes, as well as evaluate and differentiate among existing tools. Topics presented in the order that scales are constructed: how the individual items are developed, biases that can affect responses, various response options, how to select the best items in the set, how to combine them into a scale; and finally how to determine the reliability and validity of the scale. Fully updated to reflect recent developments in the field and the latest survey methods. The new edition contains updated information on generalizability theory and item response theory, and integration of qualitative research methods into scale design and testing. Including guidelines, appendices and checklists, this useful book is a must-read for any practitioner dealing with any kind of subjective measurement.