I show how abundant land and scarce labor shaped African institutions before colonial rule. I present a model in which exogenous suitability of the land for agriculture and endogenously evolving population determine the existence of land rights, slavery, and polygyny. I then use crosssectional...

We review the theoretical and empirical literature on commitment devices. A commitment device is any arrangement, entered into by an individual, with the aim of making it easier to fulfill his or her own future plans. We argue that there is growing empirical evidence supporting the proposition...

Group liability in microcredit purports to improve repayment rates through peer screening, monitoring, and enforcement. However, it may create excessive pressure, and discourage reliable clients from borrowing. Two randomized trials tested the overall effect, as well as specific mechanisms. The...

The Uniform Small Loan Law (USLL) was the Russell Sage Foundation’s primary device for fighting what it viewed as the scourge of high-rate lending to poor people in the first half of the twentieth century. The USLL created a new class of lenders who could make small loans at interest rates...

Firms spend billions of dollars each year advertising consumer products in order to influence demand. Much of these outlays are on the creative design of advertising content. Creative content often uses nuances of presentation and framing that have large effects on consumer decision making in...

Many social experiments are run in multiple waves, or are replications of earlier social experiments. In principle, the sampling design can be modified in later stages or replications to allow for more efficient estimation of causal effects. We consider the design of a two-stage experiment for...

Microcredit seeks to promote business growth and improve well-being by expanding access to credit. We use a field experiment and follow-up survey to measure impacts of a credit expansion for microentrepreneurs in Manila. The effects are diffuse, heterogeneous, and surprising. Although there is...

We were asked to discuss specific methodological approaches to evaluating three hypothetical interventions. This article uses this forum to discuss three misperceptions about randomized trials. First, nobody argues that randomized trials are appropriate in all settings, and for all questions....

The program evaluation literature for population and health policies is in flux, with many disciplines documenting biological and behavioral linkages from fetal development to late life mortality, chronic disease, and disability, though their implications for policy remain uncertain. Both macro...

This paper studies moral hazard in a sickness-insurance fund that provided the model for socialinsurance schemes around the world. The German Knappschaften were formed in the medieval period to provide sickness, accident, and death benefits for miners. By the mid-nineteenth century,...