The Relative Inequality Index (RII) is used to quantify health disparities in what way?

• A. RII measures relative differences across the social gradient; compares extreme groups; requires ranking of individuals on socioeconomic status and modeling.
• B. RII measures absolute differences; ignores ranking.
• C. RII is a measure of income inequality only.
• D. RII compares healthcare access between urban and rural populations only.

Answer: (B)

The key idea is that the Relative Index of Inequality describes health disparities as a relative difference across the whole socioeconomic gradient, not just a single absolute gap. It works by ranking people from lowest to highest socioeconomic status and treating that rank as a continuous variable in a regression model. The resulting coefficient expresses how the health outcome changes across the gradient in relative terms—often interpreted as a relative risk or rate ratio between the bottom and top of the ladder. This approach uses the entire distribution of SES, rather than focusing only on extreme groups or on absolute differences.

So, the correct view is that RII measures relative differences across the social gradient and requires ranking individuals by SES and modeling to estimate a relative disparity across the population. It is not about absolute differences (that would be the slope index of inequality), nor is it limited to income alone or to urban–rural comparisons.