THE LEVEL OF WORLD INEQUALITY: HOW MUCH CAN ONE SAY?

This paper constructs estimates of income and consumption inequality for the world (124 countries), using various measures of inequality. It then goes on to examine the possible effects of various sources of error in the estimates, and attempts to set rough limits to the size of such effects. Among the sources of error examined are purchasing power parities used for currency conversion, systematic errors in estimates of per capita incomes, differences in age structure, government tax and expenditure policy, and lifetime income effects. The paper concludes that, although the level of uncertainty in the estimates is too great to permit conclusions about, for instance, trends over time, it is clear that the level of world inequality is extreme, and that it is primarily due to differences in average incomes across countries rather than to intra‐country inequality.