Glossary term
Gini Coefficient
The Gini coefficient is a measure of income or wealth inequality, where 0 represents perfect equality and 1 represents maximum inequality under the standard scale.
Updated
Read time
What Is the Gini Coefficient?
The Gini coefficient is a measure of inequality in the distribution of income, wealth, or consumption. On the standard 0-to-1 scale, 0 represents perfect equality, where everyone has the same amount, and 1 represents maximum inequality, where one person or household has everything and everyone else has none.
Some data sources report the same concept as a Gini index from 0 to 100. A Gini index of 40 is equivalent to a coefficient of 0.40. The measure is widely used to compare inequality across countries, regions, and time periods, but it should be read with care because it compresses an entire distribution into one number.
Key Takeaways
- The Gini coefficient measures inequality across a population.
- A lower number indicates a more equal distribution; a higher number indicates a more unequal distribution.
- The measure can be applied to income, consumption, or wealth, depending on the dataset.
- World Bank data commonly reports the Gini index on a 0-to-100 scale.
- The Gini does not show where inequality sits in the distribution or why it exists.
How the Gini Coefficient Works
The Gini coefficient is based on the Lorenz curve, which compares the cumulative share of income or wealth received by the cumulative share of the population. If everyone had equal income, the Lorenz curve would follow a straight equality line. The more the actual distribution bows away from that line, the higher the Gini coefficient.
For example, a country where income is distributed relatively evenly will have a lower Gini than a country where a large share of income goes to a small share of households. The number does not say whether the country is rich or poor. A low-income country and a high-income country can have similar Gini readings but very different living standards.
How to Read the Number
Gini reading | General interpretation |
|---|---|
Closer to 0 | More equal distribution |
Middle range | Moderate inequality, with context needed |
Closer to 1 | More unequal distribution |
Reported as 0 to 100 | Same concept multiplied by 100 |
There are no universal cutoffs that make a society fair or unfair. Interpretation depends on the dataset, tax and transfer system, social services, cost of living, household size, and whether the measure uses pre-tax income, after-tax income, consumption, or wealth.
What It Reveals
The Gini coefficient is useful because it gives a compact inequality signal. Policymakers can compare inequality before and after taxes and transfers. Economists can study whether growth is broadly shared. Investors and analysts can use inequality measures to understand consumer demand, political pressure, fiscal policy, and social stability.
A rising Gini may suggest that income gains are becoming more concentrated. A falling Gini may suggest a more equal distribution. But the reason matters. Inequality could fall because lower-income households are gaining ground, or because higher-income households lost income during a recession. The number needs economic context.
Where It Can Mislead
The Gini coefficient does not show the shape of inequality. Two countries can have the same Gini with very different distributions: one may have a squeezed middle class, while another may have deep poverty and a small wealthy elite. It also does not show absolute living standards, public benefits, mobility, debt, regional inequality, or wealth concentration unless those are in the underlying data.
Data comparability is another issue. Some countries measure income; others measure consumption. Survey methods, informal income, tax records, and household definitions can differ. A Gini comparison is most useful when the data source and method are consistent.
The Bottom Line
The Gini coefficient is a powerful shorthand for inequality, but it is not a full portrait of economic well-being. It tells readers how uneven a distribution is, not whether people are financially secure, mobile, healthy, or sharing equally in growth.