Gains from Trade with Variable Trade Elasticities

We measure gains from trade in multi-sector economies with non-homothetic preferences where changes in trade costs generate reallocation of expenditure across sectors. We show how to measure the trade elasticity and how it relates to welfare. In this environment, the trade elasticity now varies both across countries and with levels of trade costs. In an application, we find that the trade elasticity varies substantially across countries and that the gains from moving from autarky to observed trade are on average between 24% and 28% greater than in a model where the trade elasticity is constant.