Open AccessFlows of knowledge from universities and federal laboratories: Modeling the flow of patent citations over time and across institutional and geographic boundaries
Author(s) -
Adam B. Jaffe,
Manuel Trajtenberg
Publication year - 1996
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.93.23.12671
Subject(s) - diffusion , citation , function (biology) , business , knowledge flow , process (computing) , economic geography , economics , econometrics , political science , knowledge management , computer science , physics , law , evolutionary biology , biology , thermodynamics , operating system
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.