Cross-country and time-series observations (4665 Country/year observations) of the Gini coefficient as reported in surveys and as calculated by WIDER.

Good for: Showing changes in income inequality during the second half of the twentieth century.
Time period: As early as 1867 but mainly from 1950′s to present.
Documentation: User guide (see the download page linked below) and individual country information sheets provide detailed source information.
Builds on: The 1997 dataset by Klaus Deininger and Lyn Squire published by the World Bank.
Produced by: UNU-WIDER, United Nations University World Institute for Development Economics Research

Annual reports from 1990 to present, downloadable in .pdf. In the chapter on Human Development Indicators, there should be a table that includes the Gini coefficient. For example, in the 2004 edition, they are in table number 14. See also the “Get Indicators” portion of their web site, where you can download an Excel table with the Gini index.

Not as comprehensive as the WIID. The documentation is helpful. Remember to use the link from this page or from the library’s databases page so you access the subscription version rather than the free one.

*The gini coefficient is a measure of inequality, derived from the Lorenz curve (measuring the area between the Lorenz curve and a hypothetical line of absolute equality). Values range from 0 to 1, with 0 representing perfect equality and 1 representing perfect inequality. It can also be expressed as a percentage and calculated differently from one source to the next, so read the documentation.

Additionally, the Gini Index is not the only measure for inequality. The Atkinson Index is another popular method for measuring inequality, and so is the Palma Ratio.

**To assure that you understand the Gini index, try the following sources:

• Measuring Inequality in general: Inequality measurement policy analysis memo from UN Development Policy and Analysis Division
• “Technical Note: Inequality Measures and their Decompositions” from the World Bank.
• Vogt, W. Paul. 2005. Dictionary of Statistics & Methodology: A Nontechnical Guide for the Social Sciences.
  Ref. HA 17 .V64 2005
• Black, John. 1997. A Dictionary of Economics.
  Ref. HB 61 .B554 1997
• World Bank. “Distribution of Income or Consumption.” World Development Indicators (print).
  Ref HC 59.15 .W656
• World Bank. “Measuring Equity: Technical Notes.” World Development Report.
  Ref. HC 59.7 .W659 2006
• "The Quality of Institutions and the Relationship Between International Trade and Inequality" from the Journal of Developing Areas, 2020.
• "The CO2 emission Gini Index and the environmental efficiency: An analysis for 60 leading world economies" from EconomiA, 2018.
• "Variance estimation of the Gini index: revisiting a result several times published" from the Journal of the Royal Statistical Society, 2013. 

Sources arguing for the Atkinson Inequality Index:

• "The statistical drift of inequality studies" from "Inequality: A Short History", 2018. Argues for using the Atkinson Index over the Gini Index.

• "Multidimensional Generalizations of the Relative and Absolute Inequality Indices: The Atkinson-Kolm-Sen Approach" from the Journal of Economic Theory, 1995. 

• "How Much Inequality Can we Explain? A Methodology and an Application to the United States" from The Economic Journal, 1995. This article compares income inequality indices using the Panel Study of Income Dynamics as a model dataset.

• "Inequality Measurement" from the United Nations, a short explanation of differences in inequality indices.

• "Income Inequality Measures" from the Journal of Epidemiology and Community Health, 2007. 

Sources to access Atkinson Inequality Data:

• United States Census Bureau - Income Inequality Data Tables. 
• "Estimation of Generalized Entropy and Atkinson Inequality Indices from Complex Survey Data" from the Oxford Bulletin of Economics and Statistics, 2006.
• "Inequality Package" - for calculating the Gini and Atkinson Indices in MatLab. 

Sources arguing for the Palma Ratio of Inequality:

• "Do Nations Just Get the Inequality They Deserve? The “Palma Ratio” Re-examined" from "Inequality and Growth: Patterns and Policy", 2016.
• "Inequality and the Tails: the Palma Proposition and Ratio" from Global Policy, 2016. 

Sources to access the Palma Ratio:

• "Putting the Gini Back in the Bottle? 'The Palma' as a Policy-Relevant Measure of Inequality", Mimeograph, 2013. 
• Global Monitoring Report from the World Bank Group, 2014-2015. 
• Income Inequality from the Organization for Economic Co-operation and Development (OECD), 2015. 
• Income Inequality, Palma Ratio from the United Nations Development Programme Human Development Reports. 

Last upated: May 4, 2016