What Is the Palma Ratio?

Economic inequality is one of the most widely discussed issues in modern society. Governments, economists, and international organizations use various measures to understand how income and wealth are distributed across populations. While the Gini coefficient and the Lorenz curve are among the best-known tools, another increasingly popular measure is the Palma ratio.

The Palma ratio focuses on the gap between the richest and poorest segments of society, offering a simple and intuitive way to assess income inequality. This article explains what the Palma ratio is, how it is calculated, why it matters, and how it compares with other measures of inequality.

Definition of the Palma Ratio

The Palma ratio is a measure of income inequality that compares the share of national income earned by the richest 10% of the population with the share earned by the poorest 40%.

It is calculated using the following formula:

Palma Ratio = Income Share of the Richest 10% ÷ Income Share of the Poorest 40%

The ratio is named after Chilean economist José Gabriel Palma, who argued that income distribution in the middle 50% of the population remains relatively stable across countries. According to Palma, most differences in inequality arise because of changes in the income shares of the richest 10% and the poorest 40%.

Understanding the Palma Ratio

The Palma ratio provides a straightforward interpretation:

• A Palma ratio of 1 means the richest 10% receive the same total income as the poorest 40%.

• A ratio greater than 1 indicates the richest 10% earn more than the poorest 40%.

• A ratio less than 1 means the poorest 40% collectively receive more income than the richest 10%, although this is uncommon.

For example:

• Richest 10% receive 30% of national income.

• Poorest 40% receive 20%.

Palma Ratio = 30 ÷ 20 = 1.5

This means the richest 10% earn one and a half times as much income as the poorest 40% combined.

Why Was the Palma Ratio Developed?

Traditional inequality measures often summarize the entire income distribution into a single number. While useful, these measures may hide important differences between income groups.

José Gabriel Palma observed that:

• The middle 50% of households tend to receive a relatively consistent share of national income across many countries.

• Most variation in inequality comes from changes at the top and bottom of the income distribution.

As a result, the Palma ratio concentrates on the groups where inequality changes the most, making it particularly useful for policymakers and researchers.

Advantages of the Palma Ratio

1. Easy to Understand

Unlike some statistical measures, the Palma ratio has a clear interpretation. People can easily understand the comparison between the richest 10% and the poorest 40%.

2. Highlights Extreme Inequality

Because it focuses on the highest and lowest income groups, the Palma ratio directly captures disparities that often concern policymakers.

3. Useful for Policy Analysis

Governments can use the Palma ratio to evaluate whether tax reforms, wage policies, or social welfare programs are improving income distribution.

4. Better Communication

The Palma ratio is often easier to explain to the public than more technical measures such as the Gini coefficient.

Limitations of the Palma Ratio

Although useful, the Palma ratio has some drawbacks.

Ignores the Middle 50%

The ratio assumes the middle half of the population remains relatively stable. While often true, this assumption does not always hold.

Limited Detail

The Palma ratio only compares two groups. It does not describe how income is distributed within the richest 10% or the poorest 40%.

Sensitive to Data Quality

Reliable household income surveys are necessary to calculate an accurate Palma ratio. Poor data collection can affect the results.

Palma Ratio vs. Gini Coefficient

Both the Palma ratio and the Gini coefficient measure inequality, but they do so differently.

The Gini coefficient provides a comprehensive summary of overall inequality, while the Palma ratio emphasizes inequality between society's richest and poorest groups.

Palma Ratio vs. Lorenz Curve

The Lorenz curve and the Palma ratio also serve different purposes.

The Lorenz curve is a graphical representation showing the cumulative share of income earned by different portions of the population. It provides a detailed picture of the entire income distribution.

The Palma ratio, on the other hand, condenses inequality into a single number that specifically compares the richest and poorest segments.

In practice, economists often use both measures together.

Real-World Applications

The Palma ratio is widely used by:

• Governments evaluating tax and redistribution policies.

• International organizations studying global inequality.

• Researchers comparing income distributions across countries.

• Development agencies assessing poverty reduction efforts.

It is especially useful when comparing countries with similar middle-income distributions but different levels of wealth concentration at the top.

Interpreting Different Palma Ratios

Here are some hypothetical examples:

Higher Palma ratios generally indicate greater income concentration among the wealthiest households.

Why the Palma Ratio Matters

Income inequality affects many aspects of society, including:

• Economic growth

• Social mobility

• Educational opportunities

• Public health

• Political stability

A rising Palma ratio may indicate that economic gains are increasingly concentrated among the richest households, while the poorest receive a shrinking share of national income. Policymakers can use this information to design more inclusive economic policies.

Conclusion

The Palma ratio is a simple yet powerful measure of income inequality. By comparing the income share of the richest 10% with that of the poorest 40%, it highlights the parts of the income distribution where inequality tends to change the most.

Although it does not provide as complete a picture as the Gini coefficient or the Lorenz curve, its clarity and policy relevance have made it an increasingly popular tool among economists, governments, and international organizations.

Used alongside other measures of inequality, the Palma ratio helps provide a more comprehensive understanding of how income is distributed within a society and whether economic growth is being shared broadly across the population.