Although the concept of randomized assignment in order to control for extraneous factors reaches back hundreds of years, the first empirical use appears to have been in an 1835 trial of homeopathic medicine. Throughout the 19th century there was primarily a growing awareness of the need for...

Field experiments rely heavily on self-reported data, but subjects may misreport behaviors, especially sensitive ones such as crime. If treatment influences survey responses, it biases experimental estimates. We develop a validation technique that uses intensive qualitative work to assess survey...

We show that extremely poor, war-affected women in northern Uganda have high returns to a package of $150 cash, five days of business skills training, and ongoing supervision. 16 months after grants, participants doubled their microenterprise ownership and incomes, mainly from petty trading. We...

Experimental economists believe (and enforce) that researchers should not employ deception in the design of experiments. The rule exists in order to protect a public good: the ability of other researchers to conduct experiments and have participants trust their instructions to be an accurate...

Economic theory predicts that in a first-price auction with equal and observable valuations, bidders earn zero profits. Theory also predicts that if valuations are not common knowledge, then since it is weakly dominated to bid your valuation, bidders will bid less and earn positive profits....

Several small, short-term, or non-experimental studies show that cognitive behavioral-informed trainings reduce antisocial behaviors for 1–2 years. But there is no large-scale, long-term research on persistence. We follow 999 high-risk men in Liberia 10 years after randomization into: 8 weeks...

We conduct a two-phase laboratory experiment, separated by several weeks. In the first phase, we conduct urn games intended to measure ambiguity aversion on a representative population of undergraduate students. In the second phase, we invite the students back with four different solicitation...