As a basic primer, the methods tutorial in short story form by Martin Ravallion is a useful resource.
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 Analyst is an economist in the Ministry of Finance in the fictional country of Labas. In the process of figuring out how to evaluate a human resource program targeted to the poor, Ms. Analyst learns the strengths and weaknesses of the main methods in ex post impact evaluation.
Topics covered include: potential outcomes notation/framework, regression with and without a comparison group, propensity scores, difference-in-differences, and instrumental variables. A key omission is regression discontinuity. The suggested reading list is mercifully short. The paper is ungated.