In this paper we estimate the gravity model allowing for the pervasive issues of heteroscedasticity and zero bilateral trade flows identified in an influential recent paper by Santos Silva and Tenreyro. We use Monte Carlo simulations with data generated using a heteroscedastic,...

Protection unconstrained by rules typically varies considerably over time. The policy disciplines introduced in the Uruguay Round in `new' areas such as agricultural, services, and developing country industrial protection will constrain, but not eliminate, this variability. The effects of these...