Compare methods

	Oaxaca-Blinder Health Decomposition	Slope Index of Inequality
Field	Social Epidemiology	Social Epidemiology
Family	Regression model	Regression model
Year of origin	1973	1997
Originator	Ronald Oaxaca; Alan Blinder (health extension popularized by Fairlie and others)	Anton E. Kunst & Johan P. Mackenbach; Adam Wagstaff et al.
Type	Regression-based decomposition of a between-group mean gap in a health outcome	Regression-based absolute measure of health inequality across ordered SES groups
Seminal source	Oaxaca, R. (1973). Male-Female Wage Differentials in Urban Labor Markets. International Economic Review, 14(3), 693-709.	Mackenbach, J. P., & Kunst, A. E. (1997). Measuring the magnitude of socio-economic inequalities in health: an overview of available measures illustrated with two examples from Europe. Social Science & Medicine, 44(6), 757-771.
Aliases	Blinder-Oaxaca Decomposition for Health Inequalities, Threefold Decomposition of Health Disparities, Detailed Decomposition of Health Gaps, Nonlinear Oaxaca-Blinder for Binary Health Outcomes	SII, Slope Index, Absolute Slope Index of Inequality, Kunst-Mackenbach Slope Index
Related	4	4
Summary	The Oaxaca-Blinder decomposition partitions the mean difference in a health outcome between two groups into a portion explained by differences in their measured characteristics and a residual, unexplained portion attributed to differences in how those characteristics translate into health. Developed independently by Ronald Oaxaca (1973) and Alan Blinder (1973) to study labor-market wage gaps, the method was imported into social epidemiology to quantify, for example, how much of a Black-White, urban-rural, or rich-poor gap in self-rated health, BMI, hypertension, or mortality is accounted for by differences in socioeconomic exposures versus differences in returns to those exposures. Group-specific regressions are estimated, the gap in fitted means is written as a function of mean covariates and coefficients, and that gap is algebraically split into an explained (composition) component and an unexplained (coefficient) component, each of which can be further decomposed variable by variable.	The slope index of inequality (SII) is a regression-based summary measure that expresses the absolute difference in a health outcome between the bottom and the top of the socioeconomic hierarchy. Rather than comparing only the most extreme groups - which discards information and is sensitive to how categories are defined - it regresses the outcome on each group's relative position in the cumulative socioeconomic distribution and reads the inequality off the fitted line. Mackenbach and Kunst's 1997 Social Science & Medicine overview made the SII, together with its relative counterpart, the recommended pair of measures for quantifying socioeconomic inequalities in health because they use the whole population and account for group sizes. The SII is measured in the natural units of the outcome - extra deaths per 100,000, additional percentage points of disease prevalence - which makes it directly meaningful for public-health and policy audiences. Wagstaff, Paci, and van Doorslaer had earlier argued that such regression-on-rank measures, alongside the concentration index, are among the few that properly reflect the socioeconomic dimension of health. The SII has become a standard tool in health-inequality monitoring across Europe and beyond.