A single summary measure of inequality in income or consumption within a population, ranging from 0 (perfect equality) to 1 (perfect inequality), derived from the Lorenz curve.
- It equals the area between the line of perfect equality and the Lorenz curve, divided by the total area under the line of equality.
- A value of 0 means everyone has the same income; a value of 1 (or 100 if expressed as a percentage) means one person holds all income.
- A higher Gini means greater inequality; it is widely reported by the World Bank, UNDP, and national surveys.
- It does not show where in the distribution inequality occurs, only the overall spread; two very different distributions can share the same Gini.
- It is read alongside the concept lorenz curve from which it is computed, and complements poverty measures like the concept multidimensional poverty index.
The 0-to-1 range, the link to the Lorenz curve, and the interpretation (higher equals more unequal) are standard inclusive-growth facts.
The Gini measures inequality, not poverty or average income; 0 is perfect equality and 1 is perfect inequality (a common reversal in options).
Inequality index from 0 (equality) to 1 (inequality), derived from the Lorenz curve; higher means more unequal.