3.3 Addressing Income and Wealth Inequality


2026 Syllabus Objectives

By the end of this topic, you should be able to:

  1. Explain the difference between income (a flow concept) and wealth (a stock concept)
  2. Explain how income and wealth inequality is measured, including the Gini coefficient
  3. Explain the economic reasons for inequality of income and wealth
  4. Explain policies used to redistribute income and wealth: minimum wage, transfer payments, progressive income taxes, inheritance and capital taxes, and state provision of essential goods and services

1. Income vs. Wealth — What Is the Difference?

Income — A Flow Concept

Income is the money a person earns or receives over a period of time. Think of it like water flowing through a pipe — it keeps coming in regularly.

Examples of income include:

  • Wages and salaries from a job
  • Rent received from a property you own
  • Interest earned on savings
  • Profits earned by a business owner

The key idea is that income is measured over a time period — for example, "I earn 2,000 dollars per month." It is called a flow because, just like a river, it keeps moving and being received continuously.

Wealth — A Stock Concept

Wealth is the total value of everything a person owns and has accumulated at a particular point in time. Think of it like water stored in a tank — it has built up over time and just sits there.

Examples of wealth include:

  • A house or land you own
  • Savings in a bank account
  • Shares in a company
  • Valuable possessions like jewellery or art

Wealth is called a stock because it is measured at one moment in time — for example, "I own assets worth 500,000 dollars today."

How Are They Linked?

Income and wealth are connected. If someone earns a high income over many years and saves or invests some of it, they will build up more wealth. So income inequality today can lead to wealth inequality in the future. People with more wealth also tend to earn more income from it (e.g. rent from properties, dividends from shares), which makes the gap between rich and poor even wider over time.


2. Measuring Income and Wealth Inequality — The Gini Coefficient

What Is Inequality?

Inequality means that income and wealth are not shared equally among people in society. There is a large gap between the richest and the poorest.

The Lorenz Curve

To understand the Gini coefficient, you first need to understand the Lorenz curve — a graph that shows how income (or wealth) is actually distributed in a country.

  • The horizontal axis (x-axis) shows the cumulative percentage of the population, from the poorest to the richest (0% to 100%).
  • The vertical axis (y-axis) shows the cumulative percentage of total income received (0% to 100%).

There is also a line of perfect equality — a straight diagonal line at 45 degrees. This line shows what income distribution would look like if everyone in the country earned exactly the same. For example, the poorest 40% of the population would earn exactly 40% of total income.

In reality, the actual Lorenz curve bows below this line. The further it bows downward (away from the 45-degree line), the more unequal the income distribution is.

The Gini Coefficient

The Gini coefficient is a single number that tells us how unequal a country's income (or wealth) distribution is. It is based on the Lorenz curve diagram.

  • On the Lorenz curve diagram, there is an area between the line of perfect equality and the actual Lorenz curve. Call this Area A.
  • There is also the area under the Lorenz curve itself. Call this Area B.
  • The Gini coefficient = Area A ÷ (Area A + Area B)

You do not need to calculate this yourself in the exam — but you must understand what the number means.

Interpreting the Gini coefficient:

Gini Coefficient ValueWhat It Means
Close to 0Near-perfect equality — everyone earns roughly the same
Close to 1Extreme inequality — almost all income is held by a tiny few
Around 0.3Relatively equal distribution (common in developed countries)
Around 0.6High inequality (common in some developing countries)

Key rule: The higher the Gini coefficient, the greater the inequality. A country with a Gini of 0.6 is more unequal than a country with a Gini of 0.3.

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