Jaffe A B, Trajtenberg M
Brandeis University, Department of Economics, Waltham, MA 02254-9110, USA.
Proc Natl Acad Sci U S A. 1996 Nov 12;93(23):12671-7. doi: 10.1073/pnas.93.23.12671.
The extent to which new technological knowledge flows across institutional and national boundaries is a question of great importance for public policy and the modeling of economic growth. In this paper we develop a model of the process generating subsequent citations to patents as a lens for viewing knowledge diffusion. We find that the probability of patent citation over time after a patent is granted fits well to a double-exponential function that can be interpreted as the mixture of diffusion and obsolescense functions. The results indicate that diffusion is geographically localized. Controlling for other factors, within-country citations are more numerous and come more quickly than those that cross country boundaries.
新技术知识跨越机构和国家边界的程度，对于公共政策和经济增长建模而言是一个极为重要的问题。在本文中，我们构建了一个关于专利后续被引用过程的模型，以此作为观察知识扩散的一个视角。我们发现，专利被授予后随时间推移的专利被引用概率，与一个双指数函数拟合得很好，该函数可被解释为扩散函数和过时函数的混合。结果表明，扩散在地理上是局部性的。在控制其他因素的情况下，国内引用比跨国引用数量更多且来得更快。
