The United States is number 4 in the 2010 HDI; in previous HDIs it was not in the top 10. Why the change?
Lifting the cap on income for the United States plays only a minor role in the change. There are seven countries with a higher income that are ranked lower than the US (Liechtenstein, Luxembourg, Singapore, United Arab Emirates, Brunei Darussalam, Qatar, and Kuwait). Even if the income was capped at $51,300 (equivalent to PPP$40,000 in 1998, expressed in $PPP2008 dollars), the USA would stay at the 4 position. Use of the mean years of schooling instead of literacy made a huge difference, however. The mean years of schooling in the United States is 0.2 years behind the top ranking Norway, whereas literacy was set to 99 per cent, but 25 high developed countries had the literacy of 99 per cent too, so the literacy couldn’t discriminate between them. In general, the geometric mean favours a well-rounded performance on all three dimensions, which worked against some of the US competitors (Sweden, Germany, and Ireland).
