The mystery of the vanishing benefits: An introduction to impact evaluation

This article provides an introduction to the concepts and methods of impact evaluation. The author provides an intuitive explanation in the context of a concrete application. The article takes the form of a short story about a fictional character's on-the-job training in evaluation. Ms. Speedy Analy st is an economist in the Ministry of Finance in the fictional country of L abas. In the process of figuring out how to evaluate a human resource progr am targeted to the poor, Ms. Analyst learns the strengths and weaknesses of the main methods of ex post impact evaluation.