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 and other inequality data 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 gross and net income inequality for 157 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. SWIID Version 2.0, July 2009. Download BibTeX citation.