The Inequality Lab
How the world's advantages are distributed.
Five demonstrations, each built on published data. They follow inequality from the circumstances of birth, through the measurement of income and wealth, to the policies that reshape it and the history that produced it.
Every figure is sourced at the foot of the page. Where a chart simplifies, the note beneath it says how.
The Birth Lottery
Rawls asked us to choose principles of justice from behind a veil of ignorance, without knowing who we would be. Every person alive has already drawn a place of birth, and none chose it.
Press the button to be born at random into one of 25 countries that together hold about 70 percent of humanity. The draw is weighted by population, so each person in these countries has the same chance of being you. The bars compare the outcome with the population-weighted average of the sample, marked by the black tick.
DataPopulation: UN World Population Prospects, 2023. Income: World Bank GNI per capita, PPP (current international dollars), 2023. Life expectancy: UN DESA, 2023. Schooling: UNDP Human Development Report 2025, 2023 values. The 25 countries are a sample; the poorest and smallest countries are underrepresented.
Life expectancy differs by thirty years and income by a factor of a hundred across these draws. All of it is settled before the person drawn has done anything.
The Champagne Glass
The 1992 UNDP Human Development Report drew world income as a champagne glass: a wide bowl for the rich and a thin stem for everyone else. Three decades later the shape persists.
Each bar is one tenth of the world's adults, from the poorest at the bottom to the richest at the top. Its width is that tenth's share of world income or wealth. Switch to wealth and the stem nearly disappears.
DataWorld Inequality Report 2022, global shares for 2021 in purchasing power parity. The report publishes the bottom 50%, middle 40%, and top 10%. The split of each group into deciles is interpolated here; group totals match the report.
An average describes almost no one in a distribution shaped like this. The world's mean income sits far above what most people receive.
The Lorenz Curve and the Gini
Max Lorenz proposed his curve in 1905; Corrado Gini derived his coefficient from the same idea in 1912. Most published statements about inequality rest on these two tools.
Line up everyone from poorest to richest and ask what share of total income the poorest p percent receive. Perfect equality gives the dashed diagonal. The further the curve sags, the larger the Gini. Move the slider, or pick a real country.
MethodThe curve assumes a lognormal income distribution with the chosen Gini (σ = √2 · Φ−1((G+1)/2)). Real distributions have heavier top tails, so the top-tenth share is understated at high Gini values. Presets: OECD Income Distribution Database via Our World in Data, Gini of equivalised household income. Hover the chart to read any point.
A single number summarizes a whole curve. Two societies with the same Gini can still differ at the top or the bottom, which is why careful work reports shares as well.
Redistribution by Welfare Regime
Esping-Andersen's Three Worlds of Welfare Capitalism (1990) sorted rich democracies into social democratic, conservative, and liberal regimes. Later work added southern European and East Asian types.
Each row shows a country's Gini twice: for market income, before taxes and transfers (open circle), and for disposable income, after them (filled circle). The line between is what the state does. Hover a row for its figures.
Market inequality varies within a narrow band across these countries. Final inequality varies far more, and the difference is made by taxes and transfers.
DataOECD Income Distribution Database, via Our World in Data: Gini of equivalised household income, total population, latest year available (2020 to 2023). Regime labels follow common usage in comparative research; the Netherlands and Ireland are frequently classed as hybrids. Public pensions count as transfers, so retirees have little market income; this raises the market-income Gini most where public pensions are large.
Rich democracies begin with similar levels of market inequality and finish far apart. Much of the inequality people experience is a policy outcome.
The Great Divergence
Kenneth Pomeranz gave the term its modern meaning in 2000. Around 1800 the richest and poorest regions of the world were separated by a factor of about three. Two centuries of uneven growth widened the gap.
Drag through time to trace average income per person in seven world regions. The log scale shows growth rates as slopes; the linear scale shows the gap as people experience it.
DataGDP per capita in 1990 international Geary-Khamis dollars, from A. Maddison, Contours of the World Economy, 1–2030 AD (2007), table A.7, for 1820, 1870, 1913, 1950, 1973, and 2008. Values between those years are interpolated on a log scale. Western offshoots are the United States, Canada, Australia, and New Zealand.
The gap between rich and poor regions is largely a creation of the last two centuries. Since 1973, Asia's growth has narrowed it for a large share of humanity, while Africa's position has slipped further.
Place of birth, the shape of the distribution, the reach of the state, and the long history of growth each set limits on individual effort. Sociology studies those limits.
Companion labThe Methods Lab →The note beneath each chart gives the source and year of every figure it uses.