Università degli Studi di Cagliari e Sassari Econometric analysis: previous results for the general KPF Main results –Importance of internal R&D expenditure –Role played by other internal factors (economic performance, agglomeration economies and national differences in production structure, institutions and others) –External effects count: Both through patenting activity and the R&D efforts in other regions A decay process of knowledge diffusion Mostly constrained by national borders (national innovation systems or social/cultural proximity ) Spatial proximity effects are enhanced when regions are technologically homogeneous
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