A methodology for identifying high R&D city-regions worldwide using patent data is presented. A heat map (kernel density estimation) approach is used which allows city-regions to be identified in areas with a high patenting intensity, a proxy for high R&D expenditure. The methodology is independent of any pre-existing administrative boundaries and it can therefore be applied to identify sub-national concentrations of R&D expenditure worldwide. This is an important advantage compared to other statistical data which is often only available at the national level. The results provide insight into the changing worldwide spatial distribution of R&D expenditure between 1997 and 2011, including the rapid rise of Asian R&D city-regions as well as less dramatic shifts among European and North American city-regions. The results also highlight some challenges of identifying high R&D city-regions and estimating R&D expenditure using patent data, and the existence of very large high R&D city-regions which encompass multiple cities. Some suggestions for improvement and further research are also proposed.
- Evolutionary economic geography