Flows of knowledge from universities and federal laboratories: modeling the flow of patent citations over time and across institutional and geographic boundaries.
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.
Brandeis University, Department of Economics, Waltham, MA 02254-9110, USA. jaffe@binah.cc.brandeis.edu
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D002170:Canada; D005060:Europe; D005062:European Union; D005843:Geography; D006077:Government Agencies; D007221:Industry; D007564:Japan; D016018:Least-Squares Analysis; D008962:Models, Theoretical; D010330:Patents as Topic; D011640:Public Policy; D012106:Research / Q000639:trends*; D013672:Technology / Q000639:trends; D014481:United States; D014495:Universities