States that pulled ahead of the pack in secondary schooling were most often in rich agricultural areas with high, and narrowlyd istributed, per capita income but moderate manufacturing activity  Income convergence among the states was exceptionally strong in the 1929 to 1947 period.B ut the states with higher secondary-school graduation rates in the 1920s achieved income levels significantly greater than a simple convergence process would predict.E ducationm attereda t the individuall evel and at that of the state. That higher levels of education caused the United States to grow more rapidly than other countries is a more difficult proposition to prove. One fact is certain, however. In the 1910 to 1940 period America pulledf ara heado f other industriael conomies in both education and income.
America had graduated from high school; the people in virtually no other country had.