The book shows how to apply validity concepts when planning and conducting an evaluation, thereby making sure that the evaluation stays true to the purposes for which it was initiated. Marc T. Braverman demonstrates that evaluating with validity means being able to answer the evaluation questions in a way that is useful, accurate, and reflective of the information needed from the evaluation. His approach is practical, with the goal of helping evaluators to conduct high-quality outcome evaluations, and he illustrates concepts with case study examples drawn from studies of intervention effectiveness over many years. The book begins by looking at the ways that validity is conceptualized and the uses to which it is put. Subsequent chapters analyze separate phases of the outcome evaluation process and the critical decisions about design and analysis that are typically required.