The World Inequality Lab (WIL) is a research laboratory and institution focused on the study of global inequality dynamics, based primarily at the Paris School of Economics. It was established to produce evidence-based research on the various dimensions of inequality, both within and between countries, to inform public debate. The WIL's origin is closely tied to the renewal of economic inequality studies in the early 2000s and the work of economists like Thomas Piketty.
The core mechanism of the WIL is the hosting and maintenance of the World Inequality Database (WID), which is the most extensive open-access public database on the historical evolution of economic inequality. The WID, which was first placed in an open-source repository in September 2013, was compiled by researchers including Facundo Alvaredo, Anthony B. Atkinson, Thomas Piketty, Emmanuel Saez, and Gabriel Zucman. The database works by combining different data sources, such as national accounts, survey data, fiscal data, and wealth rankings, to track the distribution of income and wealth, including at the very top, which surveys often miss. This methodology is often framed around the production of Distributional National Accounts (DINA) for all countries.
The WIL connects to a large international network of over 200 affiliated researchers across five continents who contribute to the database. Its key output is the World Inequality Report, which provides estimates of global income and wealth inequality, with the latest being the 2026 edition, which updates the 2022 and 2018 reports. The Lab's research has expanded beyond income and wealth to include themes like gender inequalities, environmental inequalities, and taxation and tax evasion. For instance, a recent working paper titled Land Inequality in India: Nature, History, and Markets found that the richest 10% of rural households own 44% of India's total land area. The WIL has recently developed tools like the Global Wealth Tax Simulator and welcomed the proposal for an International Panel on Inequality (IPI) to scale up global inequality monitoring.