International economics has overwhelmingly relied on Samuelson's (1954) assumption that trade costs are proportional to value. We develop a quantitative analytical framework that features both additive and multiplicative (iceberg) trade costs, building on a model of international trade with...

Casual empiricism suggests that additive trade costs, such as quotas, per-unit tariffs, and, in part, transportation costs, are prevalent. In spite of this, we have no broad and systematic evidence of the magnitude of these costs. We develop a new empirical framework for estimating additive...