Sectoral and Geographical Specificities in the Spatial Structure of Economic Activities

This work explores the spatial distribution of productive activities in the Italian manufacturing industry. We propose an econometric model which tries to disentangle location-specific from sectoral drivers in the dynamic process of spatial agglomeration. The basic idea is that the former typically apply ``horizontally'' (i.e. across all industrial sectors), while the latter unfold in the form of non-decreasing dynamic returns to the current stock of installed business units. Three different specifications of the model are tested against Italian data on the location of manufacturing activities, studying the distribution of the number of firms and employees. Our results suggest that different locations exert different structural influences on the distribution of both variables. Moreover, a significant horizontal power of ``urbanization'', which makes some locations, especially metropolitan areas, more attractive irrespectively of the sector, does emerge. However, after controlling for the latter, one is still left with very significant sector-specific forms of dynamic increasing returns to agglomeration, which vary a lot across different manufacturing activities and which plausibly have to do with sectoral-specific and localized forms of knowledge accumulation and spin-offs.