Inequality-adjusted HDI

The Inequality-adjusted Human Development Index (IHDI) extends the Human Development Index by accounting for how achievements in health, education, and income are distributed across a population, not just their averages. Designed by Sabina Alkire and James Foster for the UNDP and introduced in the 2010 Human Development Report, it discounts each HDI dimension by the inequality observed within it, using an Atkinson-class inequality measure. When there is no inequality the IHDI equals the HDI; as inequality rises the IHDI falls below it, and the percentage gap — the 'loss' — measures how much human development is eroded by being unequally shared.