We investigate the causal effect of patent rights on cumulative innovation, using large-scale data that approximate the patent universe in its technological and economic variety. We introduce a novel instrumental variable for patent invalidation that exploits personnel scarcity in post-grant...

We study the blocking effect of patents on follow-on innovation by others. We posit that follow-on innovation requires freedom to operate (FTO), which firms typically obtain through a license from the patentee holding the original innovation. Where licensing fails, follow-on innovation is...

We study the causal impact of invalidating marginally valid patents during post-grant opposition at the European Patent Office on affected inventors' subsequent patenting. We exploit exogenous variation in invalidation by leveraging the participation of a patent's original examiner in the...