Two different models - one based on local geographical externalities and the other on the variety of only locally available intermediate services - are shown to give rise to a simple, estimable relation between employment density and productivity. Using data on gross state output for the U.S.,...

Two different models - one based on local geographical externalities and the other on the variety of only locally available intermediate services - are shown to give rise to a simple, estimable relation between employment density and productivity. Using data on gross state output for the U.S.,...

The paper estimates agglomeration-effects for France, Germany, Italy, Spain, and the UK. Estimation takes into account endogeneity of the spatial distribution of employment and spatial fixed-effects. Empirical results suggest that agglomeration-effects in these European countries are only...