手法を比較

	Gini Coefficient	Index of Dissimilarity	Palma Ratio
分野	Sociology	Sociology	Sociology
系統	Process / pipeline	Process / pipeline	Process / pipeline
提唱年	1912	1955	2011 (Palma's finding); 2013–2014 (the ratio)
提唱者	Corrado Gini	Otis Dudley Duncan & Beverly Duncan	Gabriel Palma; named by Cobham & Sumner
種類	Scalar measure of statistical dispersion / inequality	Index of evenness of two groups across units	Tail-ratio inequality measure
原典	Ceriani, L., & Verme, P. (2012). The origins of the Gini index: extracts from Variabilità e Mutabilità (1912) by Corrado Gini. The Journal of Economic Inequality, 10(3), 421–443.	Duncan, O. D., & Duncan, B. (1955). A methodological analysis of segregation indexes. American Sociological Review, 20(2), 210–217.	Cobham, A., & Sumner, A. (2014). Is inequality all about the tails? The Palma measure of income inequality. Significance, 11(1), 10–13.
別名	Gini index, Gini ratio, Gini concentration ratio, G	dissimilarity index, Duncan index, D index, segregation index	Palma index, Palma measure, top10/bottom40 ratio
関連	5	5	5
概要	The Gini coefficient is the most widely used single-number summary of inequality in a distribution such as income or wealth. Introduced by the Italian statistician Corrado Gini in 1912, it equals twice the area between the Lorenz curve and the line of perfect equality, ranging from 0 when everyone has the same amount to a maximum approaching 1 when one unit holds everything.	The index of dissimilarity, often called the Duncan segregation index, measures how unevenly two groups — such as two racial or occupational groups — are distributed across a set of units like neighborhoods, schools, or occupations. It ranges from 0, when both groups have identical distributions across units, to 1, when the units are completely segregated, and has the intuitive interpretation of the share of one group that would have to relocate to achieve an even distribution.	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.