Signature
S = 75 * HI
| Inputs | Definition | Unit |
|---|---|---|
HI | Horizontal inequity index from HE-FM-HEQ-003, or any other concentration index | index without unit |
S | Percentage of need-standardised use that would have to move linearly from the richer half to the poorer half of the population, or the reverse when negative, to give an index of zero | per cent |
|---|
Function
Horizontal equity measurement function for health care delivery and finance
Maps data on the use of health care, proxies of need and compulsory health payments, for people ranked by income or another measure of living standards, to measures of horizontal equity: need-expected use from a need regression, need-standardised use, the horizontal inequity index for the delivery of care, its rule-of-75 reading, and the horizontal inequity term in the decomposition of the redistributive effect of health finance. Equal treatment for equal need is judged against the average relationship between need and use in the sample, so the vertical norm is assumed rather than tested. The grouped-data concentration index (HE-FM-HINQ-005 on the Health Inequality page and HE-FM-VEQ-002 on the Vertical Equity page) and the Kakwani index (HE-FM-VEQ-001) have their own records and are not repeated here.
Try this function
Implementations
Excel
Rule of 75 percentage in one Excel cell
With the index in a cell named HIndex, Excel returns the percentage.
=75*HIndex
Assumptions
Linear redistribution scheme behind the rule of 75
The percentage refers to one particular redistribution, a linear transfer between the richer and poorer halves of the population described by Koolman and van Doorslaer. It gives an intuitive reading of the size of the index and says nothing about how inequity would be removed in practice.
Worked examples
Rule of 75 reading of the doctor visits example
The article's horizontal inequity index of 0.06 corresponds to about 4.5 per cent of need-standardised visits moving from the richer half of the population to the poorer half.
HI = 0.06; S = 4.5
Rule of 75 reading of the Jamaica preventive care index
The World Bank guide's index of 0.1374 for need-standardised preventive care in Jamaica corresponds to about 10.3 per cent of need-standardised use moving from the richer half to the poorer half.
HI = 0.1374; S = 10.3
Common errors
Reading the rule of 75 percentage as the gap between richest and poorest
The 4.5 per cent in the article's example is a share of all need-standardised visits to be moved, while the richest quintile receives about 35 per cent more standardised visits than the poorest. Reporting 4.5 per cent as the advantage of the rich understates the gap between the extreme quintiles.
Sources
World Bank guide on the rule of 75 for a concentration index
O'Donnell O, van Doorslaer E, Wagstaff A, Lindelow M. Analyzing Health Equity Using Household Survey Data: A Guide to Techniques and Their Implementation. Washington, DC: World Bank; 2008. Chapter 8, page 96: multiplying the concentration index by 75 gives the percentage of the variable that would need to be linearly redistributed from the richer half to the poorer half of the population to arrive at an index of zero, citing Koolman and van Doorslaer (2004).
Redistribution interpretation of a concentration index of inequality
Koolman X, van Doorslaer E. On the interpretation of a concentration index of inequality. Health Economics. 2004;13(7):649-656. Abstract: redistribution interpretations of the concentration index as the share of a variable that needs redistributing from rich to poor, or the reverse, to reach an index of zero.
Canonical Identity
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