Experimentation at Scale

This paper makes the case for greater use of randomized experiments "at scale." We review various critiques of experimental program evaluation in developing countries, and discuss how experimenting at scale along three specific dimensions—the size of the sampling frame, the number of units treated, and the size of the unit of randomization—can help alleviate the concerns raised. We find that program-evaluation randomized controlled trials published over the last 15 years have typically been "small" in these senses, but also identify a number of examples—including from our own work—demonstrating that experimentation at much larger scales is both feasible and valuable.