NBER Publications by Klaus Desmet

This paper proposes a new method to measure ethnolinguistic diversity and offers new results linking such diversity with a range of political economy outcomes -- civil conflict, redistribution, economic growth and the provision of public goods. We use linguistic trees, describing the genealogical relationship between the entire set of 6,912 world languages, to compute measures of fractionalization and polarization at different levels of linguistic aggregation. By doing so, we let the data inform us on which linguistic cleavages are most relevant, rather than making ad hoc choices of linguistic classifications. We find drastically different effects of linguistic diversity at different levels of aggregation: deep cleavages, originating thousands of years ago, lead to measures of diversity th...

We present a theory of spatial development. A continuum of locations in a geographic area choose each period how much to innovate (if at all) in manufacturing and services. Locations can trade subject to transport costs and technology diffuses spatially across locations. The result is an endogenous growth theory that can shed light on the link between the evolution of economic activity over time and space. We apply the model to study the evolution of the U.S. economy in the last few decades and find that the model can generate the reduction in the employment share in manufacturing, the increase in service productivity in the second part of the 1990s, the increase in land rents in the same period, as well as several other spatial and temporal patterns.

U.S. county data for the last 20 or 30 years show that manufacturing employment has been deconcentrating. In contrast, the service sector exhibits concentration in counties with intermediate levels of employment. This paper presents a theory where local sectoral growth is driven by technological diffusion across space. The age of an industry -- measured as the time elapsed since the last major general purpose technology innovation in the sector -- determines the pattern of scale dependence in growth rates. Young industries exhibit non-monotone relationships between employment levels and growth rates, while old industries experience negative scale dependence in growth rates. The model then predicts that the relationship between county employment growth rates and county employment levels in ...