Throughout this course, we have emphasized the importance of systematically evaluating the effects of sociophysical environments on people’s behavior and health; and the efficacy of social and environmental policies and programs in fostering higher levels of mental and physical well-being in a population. Rigorous evaluations of public policies and environmental interventions provide an empirical foundation for developing evidence-based design guidelines to help ensure that future environments will be as congruent as possible with users’ needs. A number different methods and examples of environmental evaluation are presented, including laboratory experiments, observational studies, and quasi-experimental research. Also, several important criteria for evaluating the costs and benefits of environmental programs and policies are discussed, including scientific rigor (e.g., internal, external, construct, ecological validity) and social validity (e.g., cost effectiveness, feasibility, scope of impact of an intervention, and its avoidance of unintended negative side effects in the population).