Frenken, Koen; Verburg, Thijs; Oort, Frank G. van - In: Revue de l'OFCE n° 104 (2008) 1, pp. 203-218
In economic theory, one can distinguish between variety as a source of regional knowledge spillovers, called Jacobs externalities, and variety as a portfolio protecting a region from external shocks. We argue that Jacobs externalities are best measured by related variety (within sectors), while...