This paper provides an overview of the what, how, and why of program evaluation, with particular emphasis on the role of control groups, pre-and post measurement, and covariate data. Resource and environmental economists in developing countries have little training in how to conduct programme or policy evaluations of proposed environment /sustainable development projects. The paper reviews detailed examples of four methods for evaluation: randomized experiments, natural experiments, matching methods, and panel-based “difference-in-difference” (DID) estimators with a description of the pros and cons of each method. It also provides a detailed case study from South Asia as an example
