The meaning of equity in the distribution of income, the difference between equity and equality, how the distribution of income is measured (the Lorenz curve and the Gini coefficient), the causes of income inequality, and the relationship between equity and efficiency

What this dot point is asking

VCAA wants you to define equity in the distribution of income, distinguish equity from equality, explain how inequality is measured with the Lorenz curve and the Gini coefficient, identify the causes of inequality, and analyse the relationship between equity and efficiency. Expect short-response definitions and 4 to 8 mark extended responses.

The answer

Equity defined

Equity in the distribution of income means a fair distribution of income across the population. It is widely treated as a domestic economic objective because a fair distribution supports social cohesion, gives everyone access to a reasonable standard of living, and allows participation in the economy.

Equity versus equality

These are not the same thing.

• Equality means everyone receives an identical income. It is a factual, measurable state.
• Equity means a fair distribution. Fairness is a normative (value) judgement. Most people accept that some inequality is fair (rewarding effort, skill and risk-taking), but that the gap should not be so large that some people cannot meet basic needs.

So a society can be equitable without being equal. Complete equality would remove the incentive to work, train and invest, which is why equity, not equality, is the goal.

Measuring the distribution of income

The Lorenz curve. A diagram that plots the cumulative share of income (vertical axis) against the cumulative share of households, ranked from poorest to richest (horizontal axis).

• The line of equality is a 45-degree diagonal: the poorest 20 percent earn 20 percent of income, the poorest 40 percent earn 40 percent, and so on.
• The actual Lorenz curve bows below this line, because the poorest households earn less than a proportional share.
• The further the Lorenz curve bows away from the line of equality, the greater the inequality.

The Gini coefficient. A single summary number derived from the Lorenz curve. It equals the ratio of the area between the line of equality and the Lorenz curve to the total area under the line of equality.

• A Gini of 0 means perfect equality (the Lorenz curve sits on the diagonal).
• A Gini of 1 means perfect inequality (one household has all the income).
• A higher Gini means greater inequality.

Australia's Gini coefficient for disposable income is around 0.30 (ABS Survey of Income and Housing), which is moderate by OECD standards. The market-income Gini (before tax and transfers) is higher, around 0.43, showing how much redistribution the tax and transfer system achieves. Always cite the latest ABS release for current figures.

Causes of income inequality

1. Differences in skills and education. Higher qualifications command higher wages.
2. Differences in employment. Unemployment and underemployment reduce income; the unemployed rely on transfers.
3. Ownership of assets and capital. Income from property, shares and businesses is more concentrated than wage income.
4. Inheritance and wealth. Accumulated wealth passes between generations.
5. Age and stage of life. Income typically rises through a working career, then falls in retirement.
6. Discrimination and disadvantage. Gender, location and other factors affect earning capacity.
7. Globalisation and technology. Can raise returns to skilled workers and owners of capital relative to less-skilled workers.

The role of the tax and transfer system

Government redistributes income through:

• Progressive income tax. Higher earners pay a higher average rate, reducing after-tax inequality.
• Transfer payments. The Age Pension, JobSeeker, Family Tax Benefit and disability support raise the incomes of lower-income households.
• Provision of goods and services. Public health, education and housing benefit lower-income households relatively more (the "social wage").

This is why the disposable-income Gini is well below the market-income Gini.

The equity-efficiency relationship

There is often a trade-off between equity and efficiency.

• High taxes and generous transfers can reduce the incentive to work, save and invest, lowering efficiency and growth.
• Very unequal outcomes can also harm efficiency, by limiting access to education and health for the disadvantaged, wasting human potential.

So the relationship is not simple. Some redistribution can improve both equity and long-run efficiency (for example, funding education for low-income children), while excessive redistribution can blunt incentives. Policymakers seek a balance: enough redistribution to support a fair society without unduly weakening the incentives that drive growth.

Examples in context

Example 1. The tax and transfer system in action

Australia's market-income Gini (before tax and transfers) is around 0.43, but the disposable-income Gini (after tax and transfers) falls to around 0.30. The gap measures how much the progressive income tax and means-tested transfers narrow the income distribution. Check the latest ABS Survey of Income and Housing for current figures.

Example 2. Reading a Lorenz curve

If the poorest 20 percent of households receive only about 7 percent of total income while the richest 20 percent receive around 40 percent, the Lorenz curve bows well below the line of equality. The larger this bow, the larger the area used to compute the Gini coefficient, and the higher the measured inequality.

Example 3. The equity-efficiency balance

Funding free TAFE and Commonwealth Supported university places redistributes opportunity toward lower-income students. This can improve equity and, by raising the skills of the workforce, also raise long-run efficiency and productivity, showing that some redistribution need not involve a trade-off.

Try this

Q1. Distinguish between equity and equality in the distribution of income. [2 marks]

• Cue. Equality is everyone receiving the same income (a factual state); equity is a fair distribution (a normative judgement) that need not require equal incomes.

Q2. Explain how the Lorenz curve and the Gini coefficient are used to measure income inequality. [4 marks]

• Cue. The Lorenz curve plots cumulative income share against cumulative household share; the further it bows below the 45-degree line of equality, the greater the inequality. The Gini coefficient summarises this as a number from 0 (perfect equality) to 1 (perfect inequality).

Q3. Explain the trade-off between equity and efficiency that can arise from redistributing income. [4 marks]

• Cue. High taxes and transfers can reduce incentives to work, save and invest (lowering efficiency), but very unequal outcomes can also harm efficiency by limiting access to education and health; policymakers seek a balance between a fair distribution and strong incentives.