As the COVID-19 pandemic progresses, researchers are reporting findings of randomized trials comparing standard care with care augmented by experimental drugs. The trials have small sample sizes, so estimates of treatment effects are imprecise. Seeing imprecision, clinicians reading research...

This paper presents a framework for how to incorporate prior sources of information into the design of a sequential experiment. These sources can include previous experiments, expert opinions, or the experimenter's own introspection. We formalize this problem using a multi-prior Bayesian...

We evaluate a large-scale set of interventions to increase demand for immunization in Haryana, India. The policies under consideration include the two most frequently discussed tools--reminders and incentives--as well as an intervention inspired by the networks literature. We cross-randomize...

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...

Randomized controlled trials in lower-income countries have demonstrated ways to increase learning, in specific settings. This study uses a large-scale, nationwide RCT in Ghana to show the external validity of four school-based interventions inspired by other RCTs. Even though the government...

We describe the challenge of college non-completion in the U.S. and a variety of explanations for the high rate of non-completion. We then provide an overview of the implementation of and evidence from eight specific college completion interventions designed to increase college completion rates...

A randomized experiment among poor entrepreneurs tested the impact of exogenously inducing higher financial aspirations. In theory, raising aspirations could have positive effects by inducing higher effort, but could also reduce effort if unmet aspirations lead to frustration. Treatment resulted...

Attempts to curb undesired behavior through regulation gets complicated when agents can adapt to circumvent enforcement. We test a model of enforcement with learning and adaptation, by auditing vendors selling illegal fish in Chile in a randomized controlled trial, and tracking them daily using...