What is the record of policies aimed at reducing income disparities among regions within countries? Paradoxically, creating a level playing field helps disadvantaged regions more than do paternalistic protectionist policies

In the mid-2000s, the production of hearing aids shifted almost entirely to 3D printing. Using difference-in-differences and synthetic control methods, this paper examines the effects of this shift on trade flows. The analysis finds that trade increased roughly 60 percent following the...