We designed and tested a voluntary commitment product to help smokers quit smoking. The product (CARES) offered smokers a savings account in which they deposit funds for six months, after which they take a urine test for nicotine and cotinine. If they pass, their money is returned; otherwise,...

We use a clustered randomized trial, and over 16,000 household surveys, to estimate impacts at the community level from a group lending expansion at 110 percent APR by the largest microlender in Mexico. We find no evidence of transformative impacts on 37 outcomes (although some estimates have...

Causal evidence on microcredit impacts informs theory, practice, and debates about its effectiveness as a development tool. The six randomized evaluations in this volume use a variety of sampling, data collection, experimental design, and econometric strategies to identify causal effects of...

Microfinance banks use group-based lending contracts to strengthen borrowers' incentives for diligence, but the contracts are vulnerable to free-riding and collusion. We systematically unpack microfinance mechanisms through ten experimental games played in an experimental economics laboratory in...

We conducted a field experiment to measure the effect of exposure to newspapers on political behavior and opinion. Before the 2005 Virginia gubernatorial election, we randomly assigned individuals to a Washington Post free subscription treatment, a Washington Times free subscription treatment,...