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...

Based on unique Swedish historical panel data on voluntary Swedish sick insurance societies 1902-1910, we test the hypothesis od economies of scale in sick insurance provision. We report results indicating that pure insurance societies charging only premium ex ante do not exhibit returns to...