Empirical evidence suggests that investments in research and development (R&D) by older and larger firms are more spread out internationally than R&D investments by younger and smaller firms. In this paper, I explore the quantitative implications of this type of heterogeneity by assuming that...

The aim of this paper is to estimate the effect of research externalities across space, in generating innovation. We do so by using R&D and patent data for eighty-six European Regions in the 1977-1995 period. We find that spillovers exist for regions within a distance of 300 Km from each other....

We review the theoretical links between growth and agglomeration. Growth, in the form of innovation, can be at the origin of catastrophic spatial agglomeration in a cumulative process la Myrdal. One of the surprising features of the Krugman [Journal of Political Economy 99 (1991) 483499] model,...