Randomized experiments are getting more and more popular to measure the impact of social policies and programs. The goal of this course is to provide a detailed understanding of this methodology and of its results. The first part of the course will address the methodology: Why and when is a rigorous evaluation of social impact needed? What are the common pitfalls of evaluations, and why does randomization help? What are the key components of a good randomized evaluation design? How do you determine the appropriate sample size, measure outcomes, and manage data? What kind of results do you get? The second part of the course will present examples of completed field experiments in the areas of education and private sector development. The last part will discuss advantages and limitations of randomized evaluation and how they can be used to better understand global poverty. Throughout the sessions, students will be prepared to conceive a group presentation giving the main lines of a possible randomized evaluation. The course will be a balanced mix of practical and theoretical approaches.