The Evolution of Specialization in the EU15 Knowledge Space

Significant attention has been directed to processes of knowledge production in a spatial context, but little consideration has been given to the type of technological knowledge produced within specific places. In this paper we use patent co-classification data from the European Patent Office (EPO) to measure the distance between all pairs of 629 International Patent Classification (IPC) categories. A multi-dimensional scaling algorithm allows us to visualize these distances in a map of the EU15 knowledge space. We trace the evolution of that space from 1981 to 2005. The patent class distance data are combined with counts of patents by IPC categories to measure the average relatedness (specialization) of knowledge produced within each NUTS2 region. We show that knowledge specialization has increased significantly across EU15 regions over time and we report those regions that have the most specialized and the least specialized knowledge bases. Changes in the average relatedness of regional knowledge cores are decomposed to reveal the contributions of technological entry, exit and selection processes over space and time. In a final section of the paper, technological diversification and abandonment at the NUTS2 level are modeled as a function of proximity to the knowledge core of the region and to knowledge spillovers from neighboring regions that are mediated by social and spatial distance.