Research library: the key sources on global income and wealth
The datasets, reports and journal articles behind global inequality estimates — what each one measures and where to find it.
This library collects the main sources we use or recommend for anyone who wants to go deeper. We add new reports and papers as they are published.
Data and annual reports
- World Inequality Database (WID) — the core data behind WealthPercentile: income and wealth distributions for most countries, with 127 percentile groups from the bottom 1% to the top 0.001%. Definitions are documented in the WID codes dictionary.
- World Inequality Report 2026 — the World Inequality Lab’s flagship report, with country sheets summarising income and wealth shares.
- UBS Global Wealth Report — annual estimates of wealth per adult, millionaire counts and median wealth by country (successor to the Credit Suisse report).
- ECB Household Finance and Consumption Survey — the euro area’s harmonised household survey of assets, debt, income and consumption.
- US Survey of Consumer Finances — the Federal Reserve’s triennial survey of US household balance sheets, with deliberate oversampling of wealthy families.
- World Bank Poverty and Inequality Platform — survey-based income and consumption distributions, the standard source for global poverty.
- LIS Cross-National Data Center — harmonised household microdata for researchers.
- Statistics Norway: income and wealth statistics for households — register-based statistics covering the entire population, used for Norway in the calculator.
Key research papers
- Chancel, L. and Piketty, T. (2021). “Global Income Inequality, 1820–2020: the Persistence and Mutation of Extreme Inequality.” Journal of the European Economic Association 19(6), 3025–3062. Two centuries of global inequality between and within countries. Article · open version
- Piketty, T., Saez, E. and Zucman, G. (2018). “Distributional National Accounts: Methods and Estimates for the United States.” Quarterly Journal of Economics. The method that allocates all of national income to individuals — the basis of the WID income concept. PDF
- Blanchet, T., Fournier, J. and Piketty, T. (2017). “Generalized Pareto Curves: Theory and Applications.” WID working paper. The interpolation technique behind WID’s percentile groups, which we also use to build each country curve. Paper
- Davies, J. B., Sandström, S., Shorrocks, A. and Wolff, E. N. (2009). “The Level and Distribution of Global Household Wealth.” NBER working paper 15508 (published in the Economic Journal, 2011). The first systematic estimate of the world distribution of household wealth. Paper
How to use these sources
Different sources answer different questions. Surveys are good at the middle of the distribution but miss the very top; tax records capture top incomes but not people below the tax threshold; national accounts give totals but not who owns what. Modern estimates — including WID’s and ours — combine all three. When two sources disagree, check first whether they measure the same thing: per person or per household, before or after tax, and whether pensions and housing are included. Our explainer on why the same salary ranks differently walks through an example.