WIID Companion (March 2021): integrated and standardized series
This document is part of a series of technical notes describing the compilation of a new companion database that complements the World Income Inequality Database. It aims at facilitating the analysis of inequality as well as progress in achieving the global goal of reducing inequality within and across countries. This new dataset also includes an annual series reporting the income distribution at the percentile level for all citizens in the world, regardless of where they live, since 1950 to present.
A previous note described the selection of income distribution series. Since these series may differ across welfare concepts and other methods used, this technical note describes the second stage, constructing integrated and standardized country series. It discusses all the necessary adjustments conducted to construct the final series for each country, with consistent estimates of the distribution of net income per capita over the entire period for which information is available. This is mainly divided into two stages. First, integrating country series by interlinking series that overlap over time, then using a more general regression-based approach.