No inventor is an island: Social connectedness and the geography of knowledge flows in the US

Do informal social ties connecting inventors across distant places promote knowledge flows between them? To measure ties, we use a new and direct index of connectedness regions based on aggregate Facebook friendships. We well-established identification strategy that relies matching inventor citations with from examiners. Moreover, isolate the specific effect connections, above beyond formal professional (co-inventor networks) geographic proximity. identify significant robust patent citations. Further, find proximity is entirely explained by networks. also show greater for entrepreneurs or ‘garage inventors’, older ‘forgotten’ patents, technology fields. It has become increasingly important over last two decades.