Patent citations and the geography of knowledge spillovers: Evidence from inventor- and examiner-added citations

I report new evidence for localized knowledge spillovers identified by Nvithin-patent variations in the geographic matching rates of citations added by inventors and citations added by examiners. Evaluated at the mean citation lag, inventor citations are 20% more likely than examiner citations to match the country of origin of their citing patent, whereas U.S. inventor citations are 25% more likely to match the state or metropolitan area of their citing patent. The localization of intranational knowledge spillovers declines with the passage of time, but international borders present a persistent barrier to spillovers.