I am an organizational psychologist with extensive experience in the theory and practice of program evaluation. My intellectual focus is on the application of complexity to program theory, evaluation methodology, and data interpretation. Lately I have been doing research on what Evolutionary Biology and Ecology have to say to the field of Evaluation. My recent hands-on evaluation work has involved safety programs in industry, emerging safety technologies, distracted driving, implicit assumptions in program design and evaluation, and agent-based simulation of conflict and refugee scenarios. When I work I pursue three principles. 1) Respect data, trust judgment. 2) Jointly optimize methodological rigor and practical use. 3) Interventions produce complex outcomes, but evaluations should be as simple and straightforward as possible.