DO STRONGER PATENTS LEAD TO FASTER INNOVATION? THE EFFECT OF CLUSTERED SEARCH
分析两家公司在成熟与创新方法间的专利竞赛，发现专利保护强度与研发努力在创新方法上的过度集中相关，且存在最优专利强度使突破时间最短。
Abstract We analyze a patent race between two firms choosing between an established and an innovative method. The unique Markov‐perfect equilibrium coincides with the cartel solution if and only if firms have the same ability of leveraging a good innovative method or there is no patent protection. Otherwise, equilibrium efforts are clustered too much in the innovative method, as compared to the cartel benchmark. The expected time to a breakthrough is minimized at an interior patent strength. Thus, a decrease in R&D productivity can go hand‐in‐hand with a concentration of research efforts in riskier areas and stronger patent protections.