Inequality-adjusted HDI

The Inequality-adjusted Human Development Index (IHDI) is a composite indicator introduced by the United Nations Development Programme (UNDP) in the 2010 Human Development Report (the report's twentieth anniversary edition, which also unveiled the Multidimensional Poverty Index and the Gender Inequality Index). It addresses a structural weakness of the original Human Development Index (HDI), conceived by Mahbub ul Haq and Amartya Sen in 1990: the HDI reports only national averages and is blind to how achievements in health, education and income are distributed within a society. The IHDI discounts each of the three HDI dimensions according to the degree of inequality in its distribution, yielding the actual level of human development "accounting for inequality." When there is no inequality across people, the IHDI equals the HDI; the gap between the two—expressed as a percentage loss—measures the cost of inequality to human development.

Methodologically, the IHDI applies the Atkinson inequality measure (with inequality-aversion parameter ε = 1) to distributions of life expectancy, years of schooling and disposable income or consumption. The Atkinson family computes a generalised mean—specifically the geometric mean of individual achievements—so that the inequality-adjusted dimension index falls as dispersion rises. The three adjusted dimension indices are then combined by a geometric mean, mirroring the HDI's own aggregation after the 2010 reform that replaced the arithmetic mean. The headline output is the percentage overall loss in HDI due to inequality, alongside coefficient-of-human-inequality figures. Because it requires household-survey microdata on distributions, the IHDI is unavailable for some countries, and its data lags the HDI.

In practice the IHDI reveals sharp divergences masked by averages. Nordic states such as Norway and Iceland typically lose only a few percentage points, reflecting egalitarian distributions, whereas highly unequal societies in sub-Saharan Africa and South Asia register losses exceeding 25–30 percent. For India, the most-cited HDRs show losses of roughly a quarter of HDI value, with the largest erosion historically occurring in the education dimension, signalling unequal schooling access. As of the 2023/24 Human Development Report ("Breaking the Gridlock"), the UNDP continued to publish the IHDI as a core dashboard indicator; India placed in the medium human development band with a persistent double-digit inequality loss. Candidates should track the latest released figures, as ranks and loss percentages are updated with each report cycle.

For the civil-services examinations, the IHDI surfaces in the economy and current-affairs segments of UPSC General Studies Paper III, and in the human-development modules of state PSC and CSS papers. The typical question angles are: (i) distinguishing the IHDI from the plain HDI and explaining what the "loss" signifies; (ii) identifying the publishing agency (UNDP, not the World Bank) and the originating 2010 report; (iii) naming the statistical tool used (Atkinson measure, geometric mean); and (iv) interpreting why India's loss is concentrated in particular dimensions. Prelims MCQs often pair it with the MPI and GII as the 2010 trio, while Mains answers reward linking inequality-adjusted metrics to inclusive-growth and SDG-10 (reduced inequalities) policy debates.