Knowledge diffusion across regions and countries: evidence from patent citations

In particular, we find a sharp cut-off at around 25 kilometers. For longer distances the probability to cite a university patent is more or less constant. For other research organizations we find no evidence that distance plays a role. Country borders are shown to play an important role in restricting the diffusion of patents of both universities and other research organizations. These results are in line with recent literature for the U.S. and suggest that knowledge spillovers and tacit knowledge are important when using knowledge embodied in university patents.