With increasing sophistication, economists have been estimating gravity equations for five decades. Robust evidence shows that borders and distance impede trade by much more than tariffs or transport costs can explain. We therefore advocate investigation of other sources of resistance, despite...

In May 2003, the United States, Canada and Argentina launched a World Trade Organization (WTO) case against the European Union concerning its authorization regime for biotech products. In November 2006, the WTO condemned this regime. Using a gravity equation, we estimate the reduction in exports...