Knowledge Diffusion from University and Public Research. A Comparison between US Japan and Europe using Patent Citations

This paper estimates the process of diffusion and decay of knowledge from university, public laboratories and corporate patents in six countries and tests the differences across countries and across technological fields using data from the European Patent Office. It finds that university and public research patents are more cited relatively to companies’ patents. However these results are mainly driven by the Chemical, Drugs & Medical, and Mechanical fields and US universities. In Europe and Japan, where the great majority of patents from public research come from national agencies, there is no evidence of a superior fertility of university and public laboratory patents vis a` vis corporate patents. The distribution of the citation lags shows that knowledge embedded in university and public research patents tends to diffuse more rapidly relative to corporate ones in particular in the US, Germany, France and Japan.