The Paper Trail of Knowledge Spillovers: Evidence from Patent Interferences
利用1998至2014年间美国专利冲突数据，发现冲突发明人同地居住的概率比对照组高1.4至4.0倍，且地理集中度高于引用关联的发明人，表明地理距离阻碍隐性知识流动。
We show evidence of localized knowledge spillovers using a new database of US patent interferences terminated between 1998 and 2014. Interferences resulted when two or more independent parties submitted identical claims of invention nearly simultaneously. Following the idea that inventors of identical inventions share common knowledge inputs, interferences provide a new method for measuring knowledge spillovers. Interfering inventors are 1.4 to 4.0 times more likely to live in the same local area than matched control pairs of inventors. They are also more geographically concentrated than citation-linked inventors. Our results emphasize geographic distance as a barrier to tacit knowledge flows.