The Importance of innovation for the economic performance of industrialized countries has been largely stressed recently by the theoretical and empirical literature. Very few studies have carefully considered the determinants of European innovation, the productivity of its R&D and the existence...

Returns to scale to capital and the strength of capital externalities play a key role for the empirical predictions and policy implications of different growth theories. We show that both can be identified with individual wage data and implement our approach at the city-level using US Census...

This paper proposes a simple theory of a system of cities that decomposes the determinants of the city size distribution into three main components: efficiency, amenities, and frictions. Higher efficiency and better amenities lead to larger cities, but also to greater frictions through...

Productivity is high in cities partly because the urban environment acts as a self-selection mechanism. If workers have imperfect information about the quality of workers with whom they match and matches take place within cities, then high-ability workers will choose to live and work in...

We study empirically technology diffusion across countries and over time. We find significant evidence that technology diffuses slower to locations that are farther away from adoption leaders. This effect is stronger across rich countries and also when measuring distance along the south-north...

This Paper demonstrates that mall store contracts are written to internalize externalities through both an efficient allocation and pricing of space and an efficient allocation of incentives across stores. Certain stores generate externalities by drawing customers to other stores, while many...

This paper analyses the effect of different types of regional subsidies to poor regions on industrial location, employment, income inequality - between and inside regions - and welfare. We show that the impact on location of such subsidies is stronger when trade costs are low. When firms are...

We combine growth theory with US Census data on individual schooling and wages to estimate the aggregate return to human capital and human capital externalities in cities. Our estimates imply that a one year increase in average schooling in cities increases their aggregate labour productivity by...