Tp. Schultz, INEQUALITY IN THE DISTRIBUTION OF PERSONAL INCOME IN THE WORLD - HOW IT IS CHANGING AND WHY, Journal of population economics, 11(3), 1998, pp. 307-344
The variance in the logarithms of per capita GDP in purchasing power-p
arity prices increased in the world from 1960 to 1968 and decreased si
nce the mid 1970s, In the later period the convergence in intercountry
incomes more than offset any increase in within country inequality. A
pproximately two-thirds of this measure of world inequality is interco
untry, three-tenths interhousehold within country inequality, and one-
twentieth between gender differences in education. If China is exclude
d from the world sample, the decline in world inequality after 1975 is
not evident. Measuring confidently trends in household and gender ine
quality will require much improved data.