Home > Topics > Business Statistics – I > Lorenz Curve – Measuring Inequality

Lorenz Curve – Measuring Inequality

Lorenz Curve is the "Rich vs Poor" graph! It shows how unequally wealth (or anything else) is distributed. 💰


What is Lorenz Curve?

[!NOTE] Definition: A cumulative percentage curve used to measure the inequality of distribution of wealth, income, or profits.

Developed by: Max O. Lorenz (1905).


Construction Steps 🛠️

Data: Income of 5 people.

  1. Convert to Cumulative Frequencies:
    • Calculate Cumulative % of Persons (X).
    • Calculate Cumulative % of Income (Y).
  2. Draw Line of Equal Distribution:
    • A diagonal straight line from (0,0) to (100,100).
    • This represents Perfect Equality (10% people have 10% income).
  3. Plot the Curve:
    • Plot the actual Cumulative % points.
    • Join them with a smooth curve.

Interpretation 🧐

  • Line of Equal Distribution: Perfect Equality.
  • Lorenz Curve: The actual distribution.
  • Gap: The area between the Line and the Curve shows the extent of inequality.
    • Small Gap: Low Inequality (Good).
    • Large Gap: High Inequality (Bad).

Uses 🌟

  1. Wealth Distribution: To see gap between rich and poor.
  2. Business: To see if sales are concentrated in few products.
  3. Comparison: Compare inequality of two countries.

Summary

  • Lorenz Curve measures Inequality.
  • Diagonal Line = Perfect Equality.
  • Further the curve, greater the inequality.
  • Gini Coefficient is the numerical measure of this area (0 to 1).

The Bottom Line: If the curve touches the diagonal, everyone is equal. If it hugs the axes, one person owns everything! 🌍

Test Your Knowledge

Question 1 of 5

1. Lorenz Curve is used to measure:

Central Tendency
Inequality/Dispersion
Correlation
Skewness