Inequality & Poverty

Two countries can have the same average income and feel like utterly different places to live. In one, most households earn close to the average. In the other, a few people own almost everything and the rest scrape by. The average hides this. To see who actually gets what, economists need a way to picture how income is spread across a whole population.

The standard picture is the Lorenz curve (a graph of how income piles up as you move from the poorest household to the richest). You line everyone up from poorest to richest. Then you ask: what share of all income does the poorest 20 percent earn? The poorest 40 percent? And so on up to 100 percent. Plotting those running totals traces a curve.

If everyone earned exactly the same, the poorest 20 percent of people would earn 20 percent of the income, the poorest 50 percent would earn 50 percent, and so on. That perfectly equal economy traces a straight 45-degree diagonal. Real economies never do. The poorest 20 percent earn far less than 20 percent of income, so the curve sags below the diagonal. The deeper it sags, the more unequal the country.

A picture is useful, but you cannot rank countries with it. For that you need one number. The Gini coefficient (a single inequality score from 0 to 1) does the job. A Gini of 0 means everyone earns exactly the same — the Lorenz curve sits right on the diagonal. A Gini of 1 means one person earns everything and nobody else earns a cent — the curve hugs the bottom and right edges. Every real country sits between.

Where does that single number come from? Look at the two regions split by the Lorenz curve. Call the area between the diagonal and the curve A — this is the “gap” the sag opens up. Call the area underneath the curve B. The Gini coefficient is A as a share of the whole triangle under the diagonal, which is A plus B.

There is a second cut to make. The Gini of a single country measures within-country inequality — the gap between rich and poor inside one society. But there is also between-country inequality — the gap between the average person in a rich country and the average person in a poor one. A nurse earning a modest wage in a wealthy country may still out-earn a doctor in a poor one. Both gaps matter, and they can move in opposite directions at once.

Inequality is about gaps between people. Poverty is about hitting a floor. Economists draw two kinds of floor. Absolute poverty means you cannot afford basic needs — food, shelter, clean water. The World Bank marks an extreme-poverty line at about 2.15 dollars a day; below it, survival itself is at risk. Relative poverty means being poor compared with others in your own society, even if your basic needs are met. A family with a home and food can still be relatively poor if everyone around them earns far more.

Why does inequality arise in the first place? Several forces stack up. Skills and education gaps mean better-trained workers command higher pay. Technology and globalisation reward some workers handsomely — a software engineer or a global pop star — while leaving others behind. Inheritance passes wealth from one generation to the next, so advantage compounds. And discrimination blocks some people from jobs and pay they have earned.

Governments have tools to push back. Progressive taxes (where higher earners pay a higher rate) paired with transfers (cash and benefits paid to those on low incomes) shift income from top to bottom. Public education and healthcare give poorer households services they could not otherwise buy, levelling opportunity. A minimum wage sets a legal floor under pay. Each tool shrinks the gap — but none is free.