Patents, Innovation and Economic Geography

In this paper we review 20 years of quantitative research in the geography of innovation, to whose advancement patent data have contributed in a decisive way. We know now that the importance attributed by the earliest studies to knowledge externalities as an agglomeration force was excessive. Localized knowledge flows exist, and explain agglomeration, but they are largely mediated by the labor market and markets for technologies. Besides, we know now that physical distance may affect knowledge diffusion, but so do social distance between inventors as well as inter- and intra-national borders. We also witness an ongoing widening of the research focus, from local/regional to international, with migration issues concerning inventors coming to the forefront.