measurement and determinants of the I-district effect

Abstract. Why the rates of innovation per capita in the Spanish Marshallian Industrial Districts are higher than in the other Local Production Systems (including the Manufacturing Local Production Systems of Large Firms)? We analyse an exhaustive database of patents granted in Spain between 2001 and 2006 aggregated in a panel of 806 Local Labour Markets classified in seven typologies of Local Production Systems. Our analysis show that Marshallian Industrial Districts generates 30 % of Spanish patents and an innovative output per capita 47 % above the national average and 31% larger than the Manufacturing Local Production Systems of Large Firms. The econometric estimates of a fixed effects model confirm the existence of an Innovation-district effect (I-district) and its size. The I-district effect is mainly related to the presence of Marshallian district economies (specialization, specialized suppliers and social capital) and to a lesser extent to urbanization economies (density although not local market size). However, no solid evidence is found between patent intensity and other knowledge variables as university graduates, knowledge-intensive industries or ICT