LSE LSE Research Laboratory LSE
LSE Research Laboratory (RLAB)

Abstract for:

Inequality Measurement and the Rich: Why inequality increased more than we thought

Frank A  Cowell,  Emmanuel  Flachaire,  June 2018
Paper No' PEP 36: | Full paper (pdf)
Save Reference as: BibTeX BibTeX File | Endote EndNote Import File

JEL Classification: D63

Is hard copy/paper copy available? YES - Paper Copy Still In Print.
This Paper is published under the following series: Public Economics Programme Discussion Papers
Share this page: Google Bookmarks Google Bookmarks | Facebook Facebook | Twitter Twitter


Many standard inequality measures can be written as ratios with the mean in the denominator. When one income moves away from equality, both the numerator and the denominator may vary in the same direction and such indices may decrease. This anomalous behaviour is not shared by median-normalised inequality measures developed in this paper, where the mean at the denominator is replaced by the median. However, median-normalised inequality measures do not respect the principle of transfers. We show that the absolute Gini and the mean logarithmic deviation, or second Theil index, are the only measures that both avoid anomalous behaviour when one income is varied and also satisfy the principle of transfers. An application shows that the increase in inequality in the United States over recent decades is understated by the Gini index and that the mean logarithmic deviation index should be preferred in practice.