The rising popularity of randomized controlled trials (RCTs) in development applications has come with continuing debates about the merits of this approach. The paper takes stock of the issues. It argues that an unconditional preference for RCTs is questionable on three main counts. First, the...

Nudge interventions have quickly expanded from academic studies to larger implementation in so-called Nudge Units in governments. This provides an opportunity to compare interventions in research studies, versus at scale. We assemble a unique data set of 126 RCTs covering over 23 million...

We study the interpretation of regressions with multiple treatments and flexible controls. Such regressions are often used to analyze stratified randomized control trials with multiple intervention arms, to estimate value-added (for, e.g., teachers) with observational data, and to leverage the...

Governments increasingly use RCTs to test innovations before scale up. Yet, we know little about whether and how they incorporate the results of the experiments into policy-making. We follow up with 67 U.S. city departments which collectively ran 73 RCTs in collaboration with a national Nudge...

We present experimental evidence that enabling access to universal early child care for families with lower socioeconomic status (SES) increases maternal labor supply. Our intervention provides families with customized help for child care applications, resulting in a large increase in enrollment...

We present experimental evidence that enabling access to universal early child care for families with lower socioeconomic status (SES) increases maternal labor supply. Our intervention provides families with customized help for child care applications, resulting in a large increase in enrollment...

We conducted a randomized controlled trial involving nearly 700 customer-service representatives (CSRs) in a Canadian government service agency to study whether providing CSRs with performance feedback with or without peer comparison affected their subsequent organ donor registration rates....

COVID-19 vaccines are widely available in wealthy countries, yet many people remain unvaccinated. Understanding the effectiveness -- or lack thereof -- of popular vaccination campaign strategies is therefore critical. In this paper, we report results from two studies that tested strategies...