June 2018: By assessing the presence or absence of a middle class in countries around the world, researchers have found that “absolute bipolarization” of global income distribution increased substantially from 1975-2010. Authors Laurence Roope, Miguel Niño-Zarazúa and Finn Tarp used data from the UN University World Institute for Development Economics Research (UNU-WIDER) World Income Inequality Database (WIID) to inform their article titled, ‘How polarized is the global income distribution?’

WIID, as of its January 2017 update, contains income inequality statistics for 172 developed, developing and transition countries, with datasets ranging from 1961-2015. Data from WIID can be viewed using an interactive visualization tool, allowing users to view, compare and download three indicators of income inequality: Gini co-efficient, median income and mean income. Indicator data can be analyzed at the country, region and country cluster based on income level, and can be broken down by deciles, quintiles and percentiles in order to view differences between the richest and poorest sectors of society.

In addition, UN-WIDER provides open access to five databases at the global level: WIID, the Government Revenue Dataset, the Social Assistance, Politics and Institutions database and SOUTHMOD- Simulating tax and benefit policies for development. Social Accounting Matrices for select countries are also available, as are a dataset for Income Distribution in Latin America, a database for small and medium enterprises in Viet Nam and survey data for the 2015 book, ‘Growth, Structural Transformation and Rural Change in Viet Nam.’

WIID includes country-level data that can be used to track progress on SDG 8 (decent work and economic growth) and SDG 10 (reduce inequalities). The UN High-level Political Forum on Sustainable Development (HLPF) will review the national implementation of SDGs 8 and 10 in July 2019. [Publication: How Polarized is the Global Income Distribution?] [UN-WIDER Database] [Growth, Structural Transformation and Rural Change in Viet Nam]