Knowledge drives the growth of nations and regions in a competitive space-economy. Hence, we would expect a strong correlation between investments in R&D, knowledge and learning processes, on the one hand, and productivity increases, on the other. However, the empirical evidence shows consistent...

Usually, the diffusion of a non-rival market knowledge externality - called a Knowledge Spillover (KS) - is related to geographical proximity. In this paper we explore the channels through which knowledge spreads. Compared with earlier work on KS measures, this study makes a step forward by...