A must read book for students and researchers who are unfamiliar with the principles and applications of psychometrics, but are using one in their research projects. There are practically hundreds and thousands of questionnaires available measuring diverse psychological constructs. Selecting, administering, scoring and interpreting the scores of those questionnaires can be a daunting task. Questions such as ‘which questionnaire to use? ‘how to score the questionnaire?’, and ‘what the scores mean?’ are some of the common questions posed by unfamiliar users of questionnaires. This book helps to familiarize readers with the basic principles and application of questionnaire. Drawing the examples from some of the most commonly used questionnaire in sport and exercise psychology, the book provides a step-by-step approach to address common questionnaire related errors in selection, administration and interpretation of the questionnaires.