James K. Galbraith at the Institute for New Economic Thinking:
Thomas Piketty and his colleagues[1] have produced a new exposition of their empirical work, entitled the World Inequality Report 2018 (hereafter: WIR). Their purpose is to showcase the exploration of income and wealth inequalities begun with the World Top Incomes Database (Atkinson and Piketty 2010) and theorized in Piketty’s epic Capital in the XXI Century (2014). In particular the WIR concentrates on the presentation of measures and evidence; the stated goal is to inform a “deliberative process” with “more rigorous and transparent information on income and wealth” than has been available to date. In a review article published on-line and open access in Development and Change on December 24, 2018, I initiate this “deliberative process” by examining the WIR data and the claims made for it.
The ground-breaking, systematic and transparent methodology on which the WIR rests is largely the use of tax records–specifically income tax records–mined to show the income shares of tranches of the income-earning population: top one percent, top ten percent, next forty percent, and bottom fifty percent are the usual divisions. These Piketty and his colleagues argue are more complete, comprehensive, and comparable across countries and through time than the generally-used alternative, which is household or person-based surveys.
More here.