This is a list of countries by inequality-adjusted human development index (IHDI), as published by the UNDP in its 2013 and 2011 Human Development Reports. According to the 2010 Report, "the IHDI is the actual level of human development (accounting for inequality)" and the unadjusted calculations for "the HDI can be viewed as an index of “potential” human development (or the maximum IHDI that could be achieved if there were no inequality)".
The index captures the HDI of the average person in society, which is less than the aggregate HDI when there is inequality in the distribution of health, education and income. Under perfect equality, the HDI and IHDI are equal; the greater the difference between the two, the greater the inequality. In that sense, "the IHDI is the actual level of human development (taking into account inequality), while the HDI can be viewed as an index of the potential human development that could be achieved if there is no inequality."
The IHDI, estimated for 132 countries (134 countries in 2011 report), captures the losses in human development due to inequality in health, education and income. Losses in all three dimensions vary across countries, ranging from just a few percent (Czech Republic, Slovenia) up to over 40% (Namibia, Angola). Overall loss takes into account all three dimensions.
This is an experimental measure that will be subject to changes in the future. One issue is in the inequality adjusted income index, which forms a third of the overall index. Effectively countries with much lower inequality adjusted GNI will score higher in the income index than other countries who have higher inequality adjusted GNI, but higher inequality. For example, country A has GNI per capita of $40,000 (index= .858), inequality adjusted GNI per capita of $30,000 (index=.816), and country B has a GNI per capita of $18,000 (.743), inequality adjusted GNI per capita of $16,000 (.735). So country A is clearly better off by both measures. However, this is not the way the inequality adjusted income index is calculated. As the text says, "The HDI income index is adjusted for inequality in income distribution based on data from household surveys."  It is the index itself which is adjusted for inequality. Thus, for country A, the index of (.858) gets multiplied by the ratio (.1478/.166)=.642. For country B, the index of (.735) gets multiplied by the ratio (16,000/18,000)=.661. Therefore, country B has a higher income index in terms of income even though it actually receives about half the income of country B.
The table below ranks countries according to their inequality-adjusted human development index (IHDI) and compares it to their HDI. The "Loss (%)" column, given by the difference between the HDI and the IHDI and expressed as a percentage, indicates the “loss” in potential human development due to inequality. The "Rank change" column reflects a country's rank difference between both HDI and IHDI lists, when only the 132 countries (134 countries in 2011 report) with a calculated IHDI are considered.
All data is based on 2013 and 2011 estimates.