Investimento pubblico e privato in R&S: effetto di complementarietà o di sostituzione?

The purpose of this paper is to analyze the relationship between public and private research funding. Data from Eurostat are used. The methodology applies econometric models based on regression analyses. The main results are: public R&D expenditure is a complement for private R&D one, but the latter has to be higher than the former to be a determinant for economic growth of countries. These results can be affected by several factors concerning the structure of National System of Innovation as well as Triple Helix interaction. In addition this research shows that the composition of public and private magnitude of national investment in research depends on the level of country development.