手法を比較

	Watts Poverty Index	Datt-Ravallion Decomposition
分野	経済学	経済学
系統	Process / pipeline	Process / pipeline
提唱年	1968	1992
提唱者	Harold W. Watts (1968); axiomatized by Buhong Zheng (1993)	Gaurav Datt & Martin Ravallion
種類	Distribution-sensitive poverty measure	Poverty-change decomposition
原典	Zheng, B. (1993). An axiomatic characterization of the Watts poverty index. Economics Letters, 42(4), 347–353.	Datt, G., & Ravallion, M. (1992). Growth and redistribution components of changes in poverty measures: a decomposition with applications to Brazil and India in the 1980s. Journal of Development Economics, 38(2), 275–295.
別名	Watts Index, Watts Poverty Measure, Log Shortfall Poverty Index	Growth-Redistribution Decomposition, Datt-Ravallion Method, Growth and Redistribution Components, Poverty Change Decomposition
関連	3	3
概要	The Watts index, proposed by Harold Watts in 1968, was the first poverty measure to be sensitive to the distribution of income among the poor, anticipating the axiomatic poverty-measurement literature by nearly a decade. It averages, over the whole population, the natural logarithm of the ratio of the poverty line to each poor person's income. Because the log gives ever-larger weight to incomes near zero, the Watts index satisfies the strong transfer principles that the headcount and the linear poverty gap fail, and Buhong Zheng's 1993 axiomatic characterization established it as the smallest distribution-sensitive measure satisfying a natural set of axioms.	The Datt-Ravallion decomposition, introduced by Gaurav Datt and Martin Ravallion in 1992, separates the observed change in a poverty measure between two dates into a growth component — the change attributable to a shift in mean income holding the relative distribution fixed — and a redistribution component — the change attributable to a shift in the Lorenz curve holding mean income fixed. A residual captures the interaction between the two. It became the standard way to ask whether falling poverty was driven by rising average incomes or by changes in inequality, and underlies the empirical literature on pro-poor growth.