Why is agricultural productivity so low in poor countries relative to the rest of the world? Is it due to geography or constrained economic choices? We assess the quantitative role of geography and land quality for agricultural productivity differences across countries using high-resolution...

"We develop a quantitative theory of human capital with heterogeneous agents in order to assess the sources of cross-country income differences. The cross-sectional implications of the theory and U.S. data are used to restrict the parameters of human capital technology. We then assess the...