Inequality in the Distribution of Personal Income in the World: How it is Changing and Why.

The variance in the logarithms of per capita GDP in purchasing power-parity prices increased in the world form 1960 to 1968 and decreased since the mid 170s. In the later period the convergence in intercountry incomes more than offset any increase in within country inequality. Approximately two-thirds of this measure of world inequality is intercountry, three-tenths interhousehold within country inequality, and one-twentieth between gender differences in education.