This book focuses on assumptions underlyingmethods choice in program evaluation. Credible program evaluation extends beyond the accuracy of research designs toinclude arguments justifying the appropriateness of methods. An important part of this justification is explaining the assumptions made about the validity of methods. This book provides a framework for understanding methodological assumptions, identifying the decisions made at each stage of the evaluation process, the major forms of validity affected by those decisions, and the preconditions for andassumptions about those validities.Though the selection of appropriate research methodology is not a new topic within social development research, previouspublications suggest only advantages and disadvantagesof using various methods and when to use them. Thisbook goes beyond other publications to analyze the assumptions underlying actual methodological choicesinevaluation studies and how these eventually influence evaluation quality.The analysis offered issupported by a collation of assumptions collected from acase study of 34 evaluations. Due to its in-depth analysis, strong theoretical basis, andpractice examples, Credibility, Validity and Assumptions is amust-have resource for researchers, students, university professors and practitioners in program evaluation.Importantly, it provides tools for the application ofappropriate research methods in program evaluation © Springer International Publishing Switzerland 2015.