Does it matter where patent citations come from? Inventor versus examiner citations in European patents

This paper investigates whether the distinction between patent citations added by the inventor or the examiner is relevant for the issue of geographical concentration of knowledge flows (as embodied in citations). The distinction between inventor and examiner citations enables us to work with a more refined citation indicator of knowledge flows. We use information in the search reports of patent examiners at the European Patent Office to construct our dataset of regional patenting in Europe, and apply various econometric models to investigate our research question. The findings point to a significant localization effect of inventor citations, after controlling for various other factors, and hence suggest that knowledge flows are indeed geographically concentrated. This holds true also for a sub-sample of patents owned by 169 large multinational enterprises (MNEs). The results for the sample of MNEs suggest that multinational firms seek out specific regional knowledge specializations (and hence at least partly reinforce geographical concentration), but are also able to transfer knowledge "easier" over larger distances.