The Human Development Index

In 1990 the United Nations Development Programme published the first Human Development Report, which introduced the Human Development Index (HDI). Pakistani economist Mahbub ul Haq led the project, working closely with Indian economist Amartya Sen, and their goal was to shift attention from income alone to people's capabilities. The HDI combines three dimensions: a long and healthy life (life expectancy), knowledge (years of schooling) and a decent standard of living (income per person, adjusted for purchasing power).

Because income enters in logarithmic form, extra dollars count for less in rich countries than in poor ones. The index revealed that countries with similar incomes can differ widely in health and education, which raised questions about policy choices. Critics note that its weights are arbitrary and that it leaves out inequality, freedom and the environment, so the UNDP later added inequality-adjusted and gender-related versions.