Inventor collaboration and its’ persistence across European regions.

A community detection exercise on co-inventor ties across regions of EU27 and continental EFTA countries reveals that persisted collaborations cluster at a smaller geographical scale than what is observed in the full network. We find that persistent collaboration gains exceptional likelihood if regions are proximate in terms of geography, have similar technological profiles and share many common third partners.  Our results therefore offer evidence that repeated inventor collaboration drives regional innovation systems towards isolation, which is a threat for European innovation policy.