Comparer des méthodes

	Palma Ratio	Atkinson Index
Domaine	Sociology	Sociology
Famille	Process / pipeline	Process / pipeline
Année d'origine	2011 (Palma's finding); 2013–2014 (the ratio)	1970
Auteur d'origine	Gabriel Palma; named by Cobham & Sumner	Anthony Barnes Atkinson
Type	Tail-ratio inequality measure	Welfare-based, parameterized inequality index
Source fondatrice	Cobham, A., & Sumner, A. (2014). Is inequality all about the tails? The Palma measure of income inequality. Significance, 11(1), 10–13.	Atkinson, A. B. (1970). On the measurement of inequality. Journal of Economic Theory, 2(3), 244–263.
Alias	Palma index, Palma measure, top10/bottom40 ratio	Atkinson inequality measure, Atkinson's A, welfare-based inequality index
Apparentées	5	5
Résumé	The Palma ratio measures income inequality as the ratio of the income share held by the richest 10 percent of the population to the share held by the poorest 40 percent. It rests on the empirical regularity, documented by Gabriel Palma, that the middle deciles (5 through 9) capture a remarkably stable half of national income across countries, so that inequality is essentially a contest between the top and the bottom — the 'tails' of the distribution.	The Atkinson index is a welfare-based measure of inequality that incorporates an explicit, analyst-chosen parameter for how much society dislikes inequality. Introduced by Anthony Atkinson in 1970, it asks what fraction of total income could be discarded, under an equal distribution, while leaving social welfare unchanged — making the ethical judgement behind any inequality comparison transparent rather than hidden.