Book excerpt: This book discusses the crucial place that assumptions hold in conceptualizing, implementing, and evaluating development programs. It suggests simple ways for stakeholders and evaluators to 1) examine their assumptions about program theory and environmental conditions and 2) develop and carry out effective program monitoring and evaluation in light of those assumptions. A survey of evaluators from an international development agency reviewed the state of practice on assumptions-aware evaluation. This 2nd edition has been updated with further illustrations, case studies, and frameworks that have been researched and tested in the years since the first edition. Regardless of geography or goal, development programs and policies are fueled by a complex network of implicit ideas. Stakeholders may hold assumptions about purposes, outcomes, methodology, and the value of project evaluation and evaluators—which may or may not be shared by the evaluators. A major barrier to viable program evaluations is that development programs are based on assumptions that often are not well articulated. In designing programs, stakeholders often lack clear outlines for how implemented interventions will bring desired changes. This lack of clarity masks critical risks to program success and makes it challenging to evaluate such programs. Methods that have attempted to address this dilemma have been popularized as theory of change or other theory‐based approaches. Often, however, theory-based methods do not sufficiently clarify how program managers or evaluators should work with the assumptions inherent in the connections between the steps. The critical examination of assumptions in evaluation is essential for effective evaluations and evaluative thinking. "How does one think evaluatively? It all begins with assumptions. Systematically articulating, examining, and testing assumptions is the foundation of evaluative thinking... This book, more than any other, explains how to build a strong foundation for effective interventions and useful evaluation by rigorously working with assumptions." —Michael Quinn Patton, PhD. Author of Utilization-Focused Evaluation and co-editor of THOUGHTWORK: Thinking, Action, and the Fate of the World, USA. "This updated edition presents us with a new opportunity to delve into both the theoretical and practical aspects of paradigmatic, prescriptive, and causal assumptions. We need to learn, and apply these insights with the deep attention they deserve." —Zenda Ofir, PhD. Independent Evaluator, Richard von Weizsäcker Fellow, Robert Bosch Academy, Berlin, Germany. Honorary Professor, School of Public Leadership, Stellenbosch University, South Africa. “This thought-provoking book explains why assumptions are an essential condition within the theories and methodologies of evaluation; and how assumptions influence the ways that evaluators approach their work...It will enrich the ways that evaluators develop their models, devise their methodologies, interpret their data, and interact with their stakeholders.” —Jonny Morell, Ph.D., President, 4.669... Evaluation and Planning, Editor Emeritus, Evaluation and Program Planning