Standardizing the World Income Inequality Database


  • *Direct correspondence to Frederick Solt, Mailcode 4501, Department of Political Science, Southern Illinois University, Carbondale, IL 62901〈〉. For helpful comments, the author is grateful to Stephen Bloom, Mariola Espinosa, and the anonymous reviewers. The SWIID data, along with replication materials, are available at the author's website:〈〉.


Objective. Cross-national research on the causes and consequences of income inequality has been hindered by the limitations of existing inequality data sets: greater coverage across countries and over time is 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 overcome these limitations.

Methods. A custom missing-data algorithm was used to standardize the U.N. University's World Income Inequality Database; data collected by the Luxembourg Income Study served as the standard.

Results. The SWIID provides comparable Gini indices of gross and net income inequality for 153 countries for as many years as possible from 1960 to the present, along with estimates of uncertainty in these statistics.

Conclusions. By maximizing comparability for the largest possible sample of countries and years, the SWIID is better suited to broad cross-national research on income inequality than previously available sources.