We show that the effects of tariff changes on welfare and import volume can be fully characterized by their effects on the generalized mean and variance of the tariff distribution. Using these tools, we derive new results for welfare- and market-access-improving tariff changes, which imply two...

This paper develops and characterizes an index of trade policy restrictiveness defined as the uniform tariff equivalent which maintains the same volume of trade as a given set of tariffs, quota, and domestic taxes and subsidies. We relate this volume-equivalent index to the Trade Restrictiveness...

What kind of tariff reform is likely to raise welfare in situations where tariff revenue is important? Uncertainty about specification and risk from imprecise parameter estimates of any particular specification reduce the credibility of simulation estimates. A promising alternative is to develop...

The gravity model in economics was until relatively recently an intellectual orphan, unconnected to the rich family of economic theory. This review is a tale of the orphan's reunion with its heritage and the benefits that have flowed from it. Gravity has long been one of the most successful...

Does globalization widen inequality or increase income risk? In the specific factors continuum model of this paper, globalization widens inequality, amplifying the positive (negative) premia for export (import- competing) sectors. Globalization amplifies the risk from idiosyncratic relative...

The effects of geography and productivity on the global pattern of production are captured here in a specific factors gravity model. Simple enough for sharp results, the model is yet rich enough to contain the high dimensional productivity frictions in production and distribution of a many...

Most empirical policy work requires the aggregation of policies. Trade policy aggregation exemplifies the aggregation problem poignantly, with thousands of highly dispersed trade barriers. This paper provides methods of policy aggregation that are consistent with two common objectives of...

Contract enforcement is probabilistic, but the probability depends on rules and processes. A stimulus to trade may induce traders to alter rules or processes to improve enforcement. In the model of this paper, such a positive knock-on effect occurs when the elasticity of supply of traders is...

Mutual causation of predation and trade induces novel effects of commercial policy in this paper. The model can explain trade volume responses to market widening initiatives that are otherwise puzzlingly 'too big' or 'too small'. Efficient commercial policy (broadly defined) depends crucially on...

Why does illegal trade often flourish without formal enforcement, but sometimes fail? Why do illegal trade-reducing policies often fail? Why do States often appear to tolerate illegal trade? A model of trade with cops and robbers provides answers. `Safety in numbers' is a key element: the...