Interquantile differences, income inequality measurement and the Gini concentration index

Abstract

This paper studies the properties of a new income inequality index, I s, which is equal to the sum of the squares of the symmetric interquantile share differences. I s verifies most of the desired properties of an income inequality index. It will also be shown that it is closely related to Gini's concentration index. In a section at the end of the paper, an illustration is presented using data on the income distribution in various countries in 1968.