Cross-national research on the causes and consequences of income inequality has been hindered by the limitations of the existing inequality datasets: greater coverage across countries and over time has been available from these sources only at the cost of significantly reduced comparability across observations. The goal of the Standardized World Income Inequality Database (SWIID) is to meet the needs of those engaged in broadly cross-national research by maximizing the comparability of income inequality data while maintaining the widest possible coverage across countries and over time. It standardizes the United Nations University’s World Income Inequality Database, the OECD Income Distribution Database, the Socio-Economic Database for Latin America and the Caribbean generated by CEDLAS and the World Bank, Eurostat, the World Bank’s PovcalNet, the UN Economic Commission for Latin America and the Caribbean, the World Top Incomes Database, national statistical offices around the world, and many other sources while minimizing reliance on problematic assumptions by using as much information as possible from proximate years within the same country. The data collected by the Luxembourg Income Study is employed as the standard. The SWIID currently incorporates comparable Gini indices of market and net income inequality for 173 countries for as many years as possible from 1960 to the present as well as estimates of uncertainty in these statistics. A full description of the SWIID and the procedure used to generate it is presented here:

Solt, Frederick. 2009. “Standardizing the World Income Inequality Database.” Social Science Quarterly 90(2):231-242. (Final prepublication version available here.)



Download the SWIID

SWIID Version 4.0, released September 2013.


Please cite the SWIID as follows:

Solt, Frederick. 2009. “Standardizing the World Income Inequality Database.” Social Science Quarterly 90(2):231-242. SWIID Version 4.0, September 2013.
Download BibTeX citation.