方法对比

	Palma Ratio	Index of Dissimilarity	Lorenz Curve
领域	Sociology	Sociology	Sociology
方法族	Process / pipeline	Process / pipeline	Process / pipeline
起源年份	2011 (Palma's finding); 2013–2014 (the ratio)	1955	1905
提出者	Gabriel Palma; named by Cobham & Sumner	Otis Dudley Duncan & Beverly Duncan	Max Otto Lorenz
类型	Tail-ratio inequality measure	Index of evenness of two groups across units	Graphical representation of distributional inequality
开创性文献	Cobham, A., & Sumner, A. (2014). Is inequality all about the tails? The Palma measure of income inequality. Significance, 11(1), 10–13.	Duncan, O. D., & Duncan, B. (1955). A methodological analysis of segregation indexes. American Sociological Review, 20(2), 210–217.	Lorenz, M. O. (1905). Methods of measuring the concentration of wealth. Publications of the American Statistical Association, 9(70), 209–219.
别名	Palma index, Palma measure, top10/bottom40 ratio	dissimilarity index, Duncan index, D index, segregation index	Lorenz concentration curve, Lorenz diagram, cumulative share curve
相关	5	5	5
摘要	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 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 Lorenz curve is a graphical device that displays the full shape of inequality in a distribution by plotting the cumulative share of a quantity (such as income) held by the cumulative share of the population, ranked from poorest to richest. Introduced by Max Lorenz in 1905, it underlies the Gini coefficient and provides the basis for ranking distributions by inequality when one curve lies entirely above another.