International trade policies are often compared across countries and over time for a variety of purposes. Analysts use such measures as arithmetic or trade-weighted average tariffs, Non-Tariff Barrier (NTB) coverage ratios and measures of tariff dispersion. All such measures are without...

Historical evidence suggests that Mafias originally formed to provide enforcement of legitimate property rights when state enforcement was weak. We provide a general equilibrium model of Mafias as enforcement coalitions which protect property from predators. Both the level of predation and the...

The gravity model has been widely used to infer substantial trade flow effects of institutions such as customs unions and exchange rate mechanisms. McCallum [1995] found that the US-Canada border led to trade between provinces that was a factor 22 (2,200%) times trade between states and...

Corruption and imperfect contract enforcement dramatically reduce trade. This paper estimates the reduction, using a structural model of import demand in which transactions costs impose a price markup on traded goods. We find that inadequate institutions constrain trade far more than tariffs do....

Distortions in the elicitation of economic variables arise frequently. A common problem in household surveys is that reported values exhibit a significant degree of rounding. We interpret rounding as a filter that allows limited information about the relationship of interest to pass. We argue...

This paper studies the identification of nonseparable models with continuous, endogenous regressors, also called treatments, using repeated cross sections. We show that several treatment effect parameters are identified under two assumptions on the effect of time, namely a weak stationarity...

Do individuals use all information at their disposal when forming expectations about future events? In this paper we present an econometric framework to answer this question. We show how individual information sets can be characterized by simple nonparametric exclusion restrictions and provide a...

This paper provides striking confirmation of the restrictions of the structural gravity model of trade. Structural forces predicted by theory explain 95% of the variation of the fixed effects used to control for them in the recent gravity literature, fixed effects that in principle could reflect...

Are bigger markets safer? How should government policy respond to terrorist threats? Trade draws potential terrorists and economic predators into productive activity, but trade also draws terrorist attacks. Larger trade reduces the risk of terrorist attack when the wage elasticity is high,...

Much empirical work requires the aggregation of policies. This paper provides methods of policy aggregation that are consistent with two common objectives of empirical work. One is to preserve real income. The other is to preserve the real volume of activity in one or more parts of the economy....