The authors systematically document remarkably high degrees of concentration in manufacturing exports for a sample of 151 countries over a range of 3,000 products. For every country manufacturing exports are dominated by a few"big hits"which account for most of the export value and where...

Charter school competition can only work as a policy to improve public education if schools that do not contribute to this goal are allowed to fail. We estimate survival regressions to assess the effects of various factors on the probability of school failure. We find that students' test scores...