The World Income Inequality Database (WIID) presents information on income inequality for developed, developing, and transition countries. It provides the most comprehensive set of income inequality statistics available and can be downloaded for free.
The latest version of the WIID, released 28 November 2023, covers 201 countries (including historical entities) through 2022, with over 24,000 data points in total. There are now nearly 4,000 unique country-year observations in the database.
As a part of the UNU-WIDER 2019-23 work programme on transforming economies, states, and societies, we have produced a more user-friendly companion database to the classic WIID, the WIID Companion, that will greatly simplify using the WIID for cross-country comparative analysis. The WIID Companion datasets are now directly accessible in real time through our WIID Explorer, a powerful tool for accessing and analysing the most comprehensive collection of comparable income inequality statistics in the world.
After 20 years of contributions to income inequality research, the WIID now includes a new expansion — the WIID Companion — to strengthen knowledge on income inequality. The companion provides an integrated series of net per capita income inequality data for each country, curated to best reflect the trends over the time and enable comparability across countries and over time, as well as new indicators of inequality — such as the Theil, the Atkinson, and the Palma index. It also contains the income shares for the entire national distribution and offers a complete global income distribution over time, estimated to the percentile level.
The World Income Inequality Database project is also working to publish and disseminate new research on income inequality, create opportunities to engage, and host events.
Watch this space
All papers, data and opinion pieces relating to this project, as well as opportunities to engage will be available on this webpage.
UN’s 2030 Agenda for Sustainable Development
This project centrally addresses SDG 10 (reduce inequality within and among countries).
Research focal point: Rahul Lahoti
Project assistant: Iina Kuuttila
Communications: Timothy Shipp
WIID home
Previous iterations of the WIID project (2014-18)
This study examines the trajectory of global income inequality since 1981. Commonly used (relative) definitions indicate a decline in global inequality since the late 1980s. Looking ahead, it has been intuited that the influence of China's economic...
The study analyses trends in global income distribution since 1950 using a new companion WIID dataset with standardized country income percentiles. It investigate the robustness of these trends with respect to key data choices, as well as the degree...
Globally, there are several initiatives being undertaken to ensure the availability of information across countries that can be used to analyse the inequality phenomenon in and among countries. The data are easily accessible for use in comparative...
Work done by the African Centre of Excellence for Inequality Research (ACEIR) has documented the many-faceted nature of inequality in Ghana, Kenya, and South Africa. Conventionally measured inequality ranges from moderate (in Ghana) to extremely high...
Over the years, money-metric measures of inequality such as the Gini coefficient and the Palma Ratio, as frequently used in Ghana, have become useful in providing quantitative measures of welfare distribution that enable a better understanding of the...
A substantial amount of research has been conducted examining inequality in South Africa using multiple data sources. We provide an overview of this research in this paper. Furthermore, we use nationally representative survey data to estimate income...
Many countries today experience increasing or persistent income inequality, a major concern for citizens and politicians alike. This concern is...
In this paper we explore the links between international migration and income inequality. After presenting a simple model which considers the role of income distribution in individual decisions to migrate, we estimate a set of models on the...
Natural disasters cause economic damages and may exacerbate disparities in income distribution among countries across the globe. This paper employs satellite data on real-time active fire locations to evaluate the short-term impact of forest fires on...
In large parts of the world, income inequality has been rising in recent decades. Other regions have experienced declining trends in income inequality. This raises the question of which mechanisms underlie contrasting observed trends in income...
This paper investigates the importance of accounting for the profile of inequality in the analysis of institutional trust. Drawing on individual data from 82 countries around the world over the 1981–2021 period, it sheds light on the potential...
This paper investigates the evolution of the productive structure around the world and the role it plays in the difference in inequality levels, using panel data for the period from 1995 to 2018. We approximate a country’s productive structure...
Theme: 2019-23, Transforming societies
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