We estimate the effect of international trade on average labor productivity at the country level. Our empirical approach relies on summary measures of trade that, we argue, are preferable on both theoretical and empirical grounds to the one conventionally used. In contrast to the marginally...

What explains the spatial distribution of wages across US counties? I find that two of the most important factors are spatial technology diffusion and externalities due to the aggregate scale of production. One empirical finding supporting the importance of spatial technology diffusion is that...