Income distribution and inequality - TCE Economics (Tasmania)
“Explain how the distribution of income and wealth is measured and evaluate the role of government in reducing inequality in Australia.”
Income distribution describes how an economy's income is shared among its people. It is measured by the Lorenz curve and Gini coefficient. Government reduces inequality through progressive taxes and welfare transfers, but must balance equity against the efficiency costs of redistribution.
What this dot point is asking
A fair distribution of income is widely listed among the economy's goals. This dot point asks you to measure inequality, explain its causes, and evaluate whether and how government should reduce it, recognising that equity and efficiency can pull in opposite directions.
Income versus wealth
It is important to separate two related ideas. Income is a flow: the money received over a period, such as wages, profit, rent, interest and government benefits. Wealth is a stock: the value of assets owned at a point in time, such as housing, shares and superannuation, minus debts. Wealth is far more unequally distributed than income in Australia, largely because of housing and superannuation balances that accumulate over a lifetime.
A summary measure of inequality ranging from 0 to 1, where 0 means perfectly equal distribution and 1 means one person receives all income. Higher values indicate greater inequality.
Measuring the distribution
The Lorenz curve plots the cumulative share of income against the cumulative share of the population, ranked from poorest to richest. A perfectly equal distribution is the 45-degree line of equality; the further the Lorenz curve bows below that line, the greater the inequality. The Gini coefficient summarises this in a single number: it is the area between the line of equality and the Lorenz curve, as a proportion of the whole area under the line. Australia's Gini coefficient for income sits around the middle of the rich-country range.
The Lorenz curve shows inequality visually and the Gini coefficient summarises it as a number. A Gini closer to 0 means more equal; closer to 1 means more unequal. Use both when interpreting ABS distribution data.
Causes of inequality
Inequality arises from differences in wages (reflecting skills, education and bargaining power), ownership of wealth-generating assets, age and stage of life, and access to opportunity. Inheritance, housing wealth and the returns to capital can entrench inequality across generations. Some inequality is unavoidable in a market economy because it rewards skill, effort and risk-taking, which can be efficient. The policy question is how much is acceptable.
Government redistribution
Australian governments reduce inequality mainly through the tax and transfer system. The personal income tax is progressive, meaning higher earners pay a higher average rate, which narrows the gap between gross and disposable incomes. Welfare transfers, such as pensions, unemployment benefits and family payments, lift the incomes of the least well off. Government also reduces inequality in kind by providing services such as public health and education that benefit lower-income households most. Minimum wage laws set a floor under earnings.
Step 1: Start with the market (pre-tax) distribution
Before tax and benefits, suppose the richest fifth of households earns around twelve times the private income of the poorest fifth. This gap reflects wages, business profit and returns to wealth.
Step 2: Apply the progressive tax system
Higher-income households pay a higher average rate of income tax, so their disposable income falls proportionately more than that of low earners. This alone narrows the ratio.
Step 3: Add cash and in-kind transfers
The poorest fifth receives pensions, JobSeeker and family payments, and benefits most from free or subsidised health and education. Their effective income rises sharply.
Step 4: Compare the after-tax distribution
After tax and transfers, the ratio between top and bottom fifths might fall to around four or five to one. The fall in the ratio shows the tax and transfer system compressing the distribution and lowering the effective Gini coefficient.
The equity-efficiency trade-off
Redistribution has costs as well as benefits. Very high tax rates can blunt the incentive to work, save and invest, and generous benefits can in some cases weaken work incentives. Economists call this the trade-off between equity (a fairer share) and efficiency (the size of the pie). A good policy seeks to reduce poverty and extreme inequality without doing so much damage to incentives that the whole economy grows more slowly.
Students often treat income and wealth as the same thing. They are different: income is a flow over time, wealth is a stock of assets. Wealth inequality is much greater than income inequality in Australia, so always state which one the data refers to.
A strong answer defines and measures the distribution with the Lorenz curve and Gini coefficient, explains the causes of inequality, describes how the tax and transfer system redistributes, and evaluates redistribution by weighing greater equity against the efficiency costs to incentives and growth.
Exam-style questions
Questions in the style of TASC exam questions on this dot point, each with a worked answer. They are written by ExamExplained unless tagged "Past paper"; the year shows the paper a question is modelled on.
Practice6 marksUsing a Lorenz curve, explain how the Gini coefficient measures the degree of income inequality in an economy.Show worked answer →
The Lorenz curve plots the cumulative share of income (vertical axis) against the cumulative share of households ranked from poorest to richest (horizontal axis). A perfectly equal distribution is the 45-degree line of equality.
The actual distribution bows below this line: the further it bows, the more unequal the economy. The Gini coefficient turns this into one number. It is the area between the line of equality and the Lorenz curve, divided by the whole area under the line of equality, giving a value between 0 (perfect equality) and 1 (one household has all income).
A good answer sketches the diagram, labels the line of equality and the Lorenz curve, shades the gap area, and states that a larger gap (and a Gini closer to 1) means greater inequality. Australia's income Gini sits around the middle of the rich-country range.
Practice12 marksEvaluate the role of the Australian Government in reducing income inequality, with reference to the equity-efficiency trade-off.Show worked answer →
Define inequality and the equity-efficiency trade-off, set out the policy tools, then weigh benefits against costs and reach a judgement.
Tools. Government reduces inequality through a progressive income tax (higher earners pay a higher average rate), cash transfers (pensions, JobSeeker, family payments) that lift the lowest incomes, in-kind provision of health and education that benefits low-income households most, and a minimum wage floor.
Benefits. These narrow the gap between gross and disposable income, reduce poverty, and can support social cohesion and even demand (lower-income households spend a larger share of income).
Costs. Very high marginal tax rates can blunt incentives to work, save and invest, and poorly designed benefits can weaken work incentives (the efficiency cost). This is the equity-efficiency trade-off: redistribution can shrink the size of the pie even as it shares it more evenly.
Judgement. A defensible position is that targeted redistribution reducing extreme inequality is worthwhile, but it should be designed to limit the damage to incentives. Markers reward named tools, the trade-off, and a clear evaluative conclusion.