I discuss the measurement of world poverty and inequality, with particular attention to the role of purchasing power parity (PPP) price indexes from the International Comparison Project. Global inequality increased with the latest revision of the ICP, and this reduced the global poverty line...

One lingering puzzle is why voluntary contributions to public goods decline over time in experimental and real-world settings. We show that the decline of cooperation is driven by individual preferences for imperfect conditional cooperation. Many people's desire to contribute less than others,...

Geography and social links shape economic interactions. In industries, schools, and markets, the entire network determines outcomes. This paper analyzes a large class of games and obtains a striking result. Equilibria depend on a single network measure: the lowest eigenvalue. This paper is the...

Regulatory oversight of toxic emissions from industrial plants and understanding about these emissions' impacts are in their infancy. Applying a research design based on the openings and closings of 1,600 industrial plants to rich data on housing markets and infant health, we find that: toxic...

In the presence of imperfect information, voluntary certification can provide an important complement to mandatory inspections as a basis for environmental regulation in low income countries. Using data from Mexico's Clean Industry Program, we show that patterns of compliance and certification...

When regulated firms are offered compensation to prevent them from relocating, efficiency requires that payments be distributed across firms so as to equalize marginal relocation probabilities, weighted by the damage caused by relocation. We formalize this fundamental economic logic and apply it...

Pollution emitted by US manufacturers declined markedly over the past several decades, even as real manufacturing output increased. I first show that most of the decline in US manufacturing pollution has resulted from changing production processes ("technology"), rather than changes in the mix...

Charles Tiebout's suggestion that people "vote with their feet" for communities with optimal bundles of taxes and public goods has played a central role in local public finance for over 50 years. Using a locational equilibrium model, we derive formal tests of his premise. The model predicts...

Empirical work shows that a large majority of individuals get most of their information from a very small subset of the group, viz., the influencers; moreover, there exist only minor differences between the observable characteristics of the influencers and the others. We refer to these empirical...