Comparer des méthodes

	Palma Ratio	Theil Segregation Index
Domaine	Sociology	Sociology
Famille	Process / pipeline	Process / pipeline
Année d'origine	2011 (Palma's finding); 2013–2014 (the ratio)	1971
Auteur d'origine	Gabriel Palma; named by Cobham & Sumner	Henri Theil & Anthony Finizza
Type	Tail-ratio inequality measure	Entropy-based multigroup segregation 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.	Theil, H., & Finizza, A. J. (1971). A note on the measurement of racial integration of schools by means of informational concepts. Journal of Mathematical Sociology, 1(2), 187–193.
Alias	Palma index, Palma measure, top10/bottom40 ratio	Theil's H, information theory index, entropy segregation index, multigroup entropy 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.	Theil's information index, denoted H, is an entropy-based measure of segregation that, unlike the two-group dissimilarity index, handles any number of groups at once. It compares the diversity (entropy) found within each unit to the diversity of the whole population: segregation is high when units are internally homogeneous even though the overall population is diverse. Its defining virtue is exact decomposability across nested levels and across groups.