The production of high-quality goods is often viewed as a precondition for export success and economic development. We provide the first evidence that countries' import tariffs affect the rate at which they upgrade product quality. Our analysis uses highly disaggregated data covering exports from 56 countries across 10,000 products to the United States using a novel approach to measure quality. As predicted by distance-to-the-frontier models, we find that lower tariffs are associated with quality upgrading for products close to the world quality frontier, whereas lower tariffs discourage quality upgrading for products distant from the frontier.

This paper estimates the agglomeration benefits that arise from vertical linkages between firms. We identify the agglomeration benefits off the spatial variation in firms' nominal wages. Using unusually detailed intermediate input data, we take account of the location of input suppliers to estimate cost linkages; and the location of demand from final consumers and other firms to estimate demand linkages. The results show that the externalities that arise from demand and cost linkages are quantitatively important and highly localized. An increase in either cost or demand linkages from the 10th to the 90th percentile increases wages by more than 20%.