Patent rights, innovation, and firm exit
利用美国联邦巡回法院的专利诉讼数据，研究发现专利无效判决使专利持有者五年内专利申请量平均减少50%，对中小企业影响显著，尤其当面临众多大竞争对手时，且会提高小企业退出专利活动的概率。
Abstract We study the causal impact of patent invalidation on subsequent innovation and exit by patent holders. The analysis uses patent litigation data from the US Federal Circuit Court and exploits random allocation of judges to control for endogeneity of the decision. Invalidation causes patent holders to reduce patenting over a five‐year window by 50% on average, but the effect is heterogeneous. The impact is large for small‐ and medium‐sized firms, particularly where they face many large competitors, and for patents central to their research portfolio. We find no significant effect for large firms. Invalidation also increases exit from patenting by small firms.