A randomized encouragement design yields null average effects of a credit builder loan (CBL) on consumer credit scores. But machine learning algorithms indicate the nulls are due to stark, offsetting treatment effects depending on baseline installment credit activity. Delinquency on preexisting loan obligations drives the negative effects, suggesting that adding a CBL overextends some consumers and generates negative externalities on other lenders. More favorably for the market, CBL take-up generates positive selection on score improvements. Simple changes to CBL practice, particularly to provider screening and credit bureau reporting, could ameliorate the negative effects for consumers and the market.

We show that a number of noncognitive skills and preferences, including patience and identity, are malleable in adults, and that investments in them reduce crime and violence. We recruited criminally engaged men and randomized one-half to eight weeks of cognitive behavioral therapy designed to foster self-regulation, patience, and a noncriminal identity and lifestyle. We also randomized $200 grants. Cash alone and therapy alone initially reduced crime and violence, but effects dissipated over time. When cash followed therapy, crime and violence decreased dramatically for at least a year. We hypothesize that cash reinforced therapy's impacts by prolonging learning-by-doing, lifestyle changes, and self-investment.

We exploit the principles of choice architecture to evaluate interventions in the market for reloadable prepaid cards. Participants are randomized into three card menu presentation treatments—the market status quo, a regulation-inspired reform, or an enhanced reform designed to minimize attribute overload—and offered choices based on prior structural estimation of individual preferences. Consumers routinely choose incorrectly under the status quo, with tentative evidence that the regulation-inspired presentation may increase best card choice and clear evidence that the enhanced reform reduces worst card choice. Welfare analysis suggests the regulation-inspired presentation offers modest gains, while the enhanced policy generates substantial benefits.