An elementary characterization of the Gini index

• We offer an original and novel characterization for the Gini index.
• The treatment of distributions that maintain the same income ordering is essential.
• The characterization works very well for the discrete case and is simple.
• The axioms are imposed directly on the index and not on welfare orderings.
• A simpler way to compute the Gini index is derived.

The Gini index is one of the most used indicators of social and economic inequality. In this paper we characterize the Gini index as the unique function that satisfies the properties of scale independence, symmetry, standardization and comonotone separability. Furthermore, we propose a simpler way to compute it.