In the 1920s, the United States substantially reduced immigrant entry by imposing country-specific quotas. We compare local labor markets with more or less exposure to the national quotas due to differences in initial immigrant settlement. A puzzle emerges: the earnings of existing US-born...

The introduction of immigration quotas in the 1920s fundamentally changed US migration policy. We exploit this policy change to estimate the effect of immigration on local economic growth and industry development. Our analysis demonstrates that areas with larger pre-existing communities of...

We examine the economic impact of high-yielding crop varieties (HYVs) in developing countries 1960-2000. We use time variation in the development and diffusion of HYVs of 10 major crops, spatial variation in agro-climatically suitability for growing them, and a differences-in-differences...

This paper examines the long-run effects of the 1906 San Francisco Earthquake on the spatial distribution of economic activity in the American West. Using variation in the potential damage intensity of the earthquake, we show that more severely affected cities experienced lower population...

This Working Document provides an estimate of China's impact on the growth rate of resource-rich countries since its WTO accession in December 2001. The authors' empirical approach follows the logic of the differences-in-differences estimator. In addition to temporal variation arising from the...