Robert F. (The University of North Carolina at Chapel Hill, USA) DeVellis & Carolyn T. (The University of North Carolina at Chapel Hill, USA) Thorpe 
Scale Development : Theory and Applications [EPUB ebook] 
Theory and Applications

Scale Development: Theory and Applications, by Robert F. De Vellis and new co-author Carolyn T. Thorpe, demystifies measurement by emphasizing a logical rather than strictly mathematical understanding of concepts. The Fifth Edition includes a new chapter that lays out the key concepts that distinguish indices from scales, contrasts various types of indices, suggests approaches for developing them, reviews validity and reliability issues, and discusses in broad terms some analytic approaches. All chapters have been updated, and the book strikes a balance between including relevant topics and highlighting recent developments in measurement while retaining an accessible, user-friendly approach to the material covered.