Determinants of knowledge flows and their effect on economic growth.

This thesis consists of three essays that analyse the determinants of the diffusion of knowledge and their impact in terms of economic growth. The first essay analyses the patterns of diffusion of knowledge between European regions during the period 1981-2000. Knowledge flows are measured by two variables: patent citations and collaboration among inventors. A modified gravity model is estimated to show that geographical proximity and territorial borders are important barriers to knowledge flows during the period analysed and that their effects are greater for technological collaboration than for patent citation. We show that inventor propensity to collaborate within the same country decreases and inventor propensity to cite inventors residing in the same country increases. We show also that the geographical distance effect decreases only for inventor collaboration. Finally, we show that the EU enlargement processes during the period analysed have favoured knowledge flows between old and new EU members, although with significant differences for the two measures of knowledge flows. The second essay analyses the impact of knowledge capital on the economic growth of Italian regions for the period 1995-2007. To measure regional knowledge capital we use indicators for the processes of knowledge creation, i.e. R&D and patents, and the processes of diffusion of knowledge, i.e. patent citations and inventor mobility. We use a technology gap model to show that the economic growth of Italian regions can be explained by internal R&D activities and by the interregional mobility of inventors. The third essay analyses the impact of knowledge flows on economic performance at firm level. It distinguishes between various sources of knowledge flows, i.e. suppliers, customers, rivals and research institutions, and between two types of innovative activities, i.e. sales realized by products new to the firm but not to the market (imitation) and sales realized by products new to the firm and to the market (innovation). We show that knowledge flows from rivals lead to more imitation, while knowledge flows from customers and research institutions enhance original innovation.