I formulate and estimate a model of externalities within countries and technological interdependence across countries. I find that external returns to scale to physical capital within countries are 8 percent; that a 10 percent increase of total factor productivity of a country's neighbors raises...

The Industrial Revolution was characterized by technological progress and an increasing capital intensity. Why did real wages stagnate or fall in the beginning? I answer this question by modeling the Industrial Revolution as the introduction of a relatively more capital intensive production...

We estimate the aggregate long-run elasticity of substitution between more and less educated workers (the slope of the demand curve for more relative to less educated workers) at the US state level. Our data come from the (five)1950-1990 decennial censuses. Our empirical approach allows for...

The dismal growth performance of Africa is the worst economic tragedy of the XXth century. We document the evolution of per capita GDP for the continent as a whole and for subset of countries south of the Sahara desert. We document the worsening of various income inequality indexes and we...