Previous versions of the WIID
On this page you can find the previous versions of WIID, including information about data updates. In addition to Excel and Stata files (Stata not avaialble for WIID2.0) you can access the user guides and revision notes.
Please contact the database manager for any questions on the database.
WIID4 is a major update of the previous version of the database, WIID3.4.
WIID4 is a major database update. This version includes many key changes to the structure of the database, and corrects for inconsistencies found in the previous edition. The data covers 189 countries (including historical entities), with over 11,000 data points in total. The latest observations reach the year 2017.
Please cite this database version as: ‘UNU-WIDER, World Income Inequality Database (WIID), 19 December 2018’.
WIID3.4 is an update of the third major revision of the database, WIID3.
WIID3.4 is an update to WIID3. This version includes observations for six additional countries. The data cover 182 countries with 8,817 observations and now reach the year 2015.
More information about the observation composition cen be found here.
Please cite this database version as UNU-WIDER, ‘World Income Inequality Database (WIID3.4), https://www.wider.unu.edu/project/wiid-world-income-inequality-database’.
WIID3.3 is an update of the third major revision of the database, WIID3.
WIID3.3 is an update to WIID3. This update includes observations for eight more years, with latest observations now reaching the year 2013.
Please cite this database version as UNU-WIDER, ‘World Income Inequality Database (WIID3c)’, September 2015, https://www.wider.unu.edu/project/wiid-world-income-inequality-database'.
WIID3.0 is a checked and corrected version of WIID2.0.
WIID3.0 is a checked and corrected version of WIID2.0. This version includes new estimates from National Survey statistics obtained from the respective country official websites, the Socio-Economic Database for Latin America and the Caribbean, Transmonee, Luxembourg Income Study database, OECD and Eurostat.
The updated data covers new countries, with nearly 2000 additional observations. The latest observations now reach the year 2012.
Please cite this database version as ‘UNU-WIDER, ‘World Income Inequality Database (WIID3.0A)’, June 2014, https://www.wider.unu.edu/project/wiid-world-income-inequality-database’.
WIID2.0 is a checked and corrected version of WIID1.
WIID2 is a checked and corrected version of WIID1. It includes a new update of the Deininger & Squire database from the World Bank, new estimates from the Luxembourg Income Study and Transmonee, and other new sources as they have became available. WIID2a contains fewer points of data than WIID1 as some overlaps between the old Deininger & Squire data and estimates included by WIDER have been eliminated along with some low quality estimates adding no information. In addition to the Gini coefficient and quintile and decile shares, survey means and medians along with the income shares of the richest 5% and the poorest 5% have been included in the update. In addition to the Gini coefficient reported by the source, a Gini coefficient calculated using a new method developed by Tony Shorrocks and Guang Hua Wan is reported. The method estimates the Gini coefficient from decile data almost as accurately as if unit record data were used.
Please cite this database version as 'UNU-WIDER World Income Inequality Database, Version 2.0c, May 2008, https://www.wider.unu.edu/project/wiid-world-income-inequality-database'.