The Paper Trail of Knowledge Spillovers: Evidence from Patent Interferences

摘要

We present new evidence of localized knowledge spillovers using a novel database of patent interferences-instances of simultaneous, identical invention by multiple independent parties. By evidence of common, identical invention, interfering inventors share common knowledge inputs. Interfering inventor pairs show significant geographic localization compared with the counterfactual of inventor pairs sharing similar invention dates and technology classification. Thus, our results provide verification of the existence of localized knowledge spillovers and are distinct from the literature using patent citations. Interfering inventor pairs are even more localized compared with cited-citing inventor pairs, consistent with the Jaffe, Trajtenberg, and Henderson (1993) conjecture that citations are a lower bound on the strength of localized knowledge spillovers.