This paper investigates the determinants of co--inventor tie formation using micro--data on genomic patents from 1990 to 2006 in France. In a single analysis, we consider the relational and proximity perspectives that are usually treated separately. In order to do so, we analyse various forms of proximity as alternative driving forces behind network ties that occur within existing components (i.e. closure ties) as well as those between two distinct components (i.e. bridging ties). In doing so, we contrast network and proximity determinants of network formation and we investigate to what extent social networks allow economic actors to cross over geographical, technological and organizational boundaries.

This paper investigates how network relations, proximity and their interplay affect collaboration and their inventive performance. Using patent citations as a proxy for patent quality, we investigate how the network and proximity characteristics of co--inventors enable them to access different sources of knowledge, in different geographical and organizational contexts, and finally affect the quality of inventive collaboration. Our findings enable to address the proximity paradox, which states that proximity facilitates collaboration and knowledge sharing, but it does not necessarily increase innovative performance, too much proximity may even harm innovation (Boschma and Frenken, 2009;Broekel and Boschma, 2011).