Why is GDP per capita (PPP US$) used over GDP per capita (US$)?
The human development index (HDI) attempts to make an assessment of 174 very diverse countries, with very different price levels. GDP per capita (PPP US$) accounts for price differences between countries and therefore better reflects people’s living standards. In theory, at the PPP (Purchasing Power Parity) rate, 1 PPP dollar has the same purchasing power in the domestic economy as 1 US dollar has in the US economy. Is the HDI comparable over time? Yes, the HDI is comparable over time. HDR 2000 presents a time series in HDI for 1975, 1980, 1985, 1990, and 1998. This time series uses the latest methodology and most up-to-date data. Is the HDI comparable across Human Development Reports? Due to updates in the data series, as well as changes in the methodology of the HDI, the HDI presented in the 1990 through 2000 reports is not comparable over time. However, as the above answer indicates, time series data is available in Table 6 of Human Development Report 2000. Why was the HDI methodolo
