Stephen N. Haynes & John D. Hunsley 
Scientific Foundations of Clinical Assessment [PDF ebook] 

Scientific Foundations of Clinical Assessment is a user-friendly overview of the most important principles and concepts of clinical assessment. It provides readers with a science-based framework for interpreting assessment research and making good assessment decisions, such as selecting the best instruments and measures and interpreting the obtained assessment data. Written in a direct and highly readable fashion, with plenty of clinical examples that illustrate the relevance of psychometric principles and assessment research, this text is one every professional and graduate student needs to read. The second edition is expanded and fully updated, and includes additional coverage of the principles and methods of developing new assessment instruments.