This result is robust to a large set of checks (cf. appendices E and F). What’s behind it? Turns out social networks matter largely through their influence on the mobility of employees in the mining sector. Indeed, fracking relies heavily on itinerant workers commuting long distance. 6/7

I find that friendship ties play an important role in the spillover of a local shock on wage and job outcomes across places, even when they are far apart. Controls for exposure through distance or industry linkages don’t matter. In fact, geography loses the horse race to social networks. 5/7

To answer this question, I combine comprehensive FB data on friendships with info on oil and gas production during the US fracking boom to construct a measure of social exposure to distant economic shocks. Through social ties, even places far away from extraction sites are exposed to fracking! 3/7