Metropolitan Patenting, Inventor Agglomeration and Social Networks: A Tale of Two Effects

We investigate the separate effects on metropolitan patenting in the United States of inventor agglomeration and the structure of social networks linking inventors within and across metropolitan areas. Using patent data we have been able to assign a metropolitan location to individual inventors, link inventors who have co-authored patents, and characterize the structural features of the network of connections linking inventors. We find that inventors are disproportionately agglomerated in the larger metropolitan areas. Our findings also indicate that while agglomeration of inventors and agglomeration of co-patenting relationships both have a positive effect on metropolitan patenting output, inventor agglomeration is a much stronger determinant. Once important socio-economic characteristics of metropolitan areas are controlled for, structure features of inventor networks have small effects on metropolitan patenting.