The geography of duplicated inventions: evidence from patent citations
研究发现，近期和即将出现的发明因竞争激励和本地化知识流动，在短地理距离内重复概率更高；而较旧发明的重复更可能发生在长距离，因为对技术存在的认知较低。
The geography of duplicated inventions: evidence from patent citations. Regional Studies. Innovators often claim inventions that turn out to duplicate, at least in part, existing ones. This paper advances the claim that for recent and upcoming inventions, competitive incentives are high, and localized knowledge flows increase the probability of duplication. Therefore, over a brief period of time the probability of duplication is higher at short geographical distance. Conversely, the duplication of less recent inventions is more likely at long distance as a consequence of a lower awareness of the existence of a technology. This claim is supported by coherent descriptive and multivariate evidence using data on patent citation categories from the European Patent Office (EPO).