The original HDI methodology has been revised somewhat for this 20th anniversary edition of the Human Development Report. How is it different?
As in past Human Development Reports, the HDI remains a composite index that measures progress in the three basic dimensions—health, knowledge and income. Under the previous HDI formula, health was measured by life expectancy at birth; education or “knowledge” by a combination of the adult literacy rate and school enrolment rates (for primary through university years); and income or standard of living by GDP per capita adjusted for purchasing-power parity (PPP US$). Health is still measured by life expectancy at birth. But the 2010 HDI measures achievement in knowledge by combining the expected years of schooling for a school-age child in a country today with the mean years of prior schooling for adults aged 25 and older. The income measurement, meanwhile, has changed from purchasing-power-adjusted per capita Gross Domestic Product (GDP) to purchasing-power-adjusted per capita Gross National Income (GNI); GNI includes remittances and foreign assistance income, for example, providing a
