What the UNDP's Human Development Index measures

Background

The Human Development Index (HDI) is UNDP's summary measure of average achievement in key dimensions of human development. It covers three dimensions: a long and healthy life, being knowledgeable, and having a decent standard of living. Health is measured through life expectancy at birth. Education is measured through mean years of schooling for adults aged 25 and above, and expected years of schooling for children of school-entering age. Standard of living is measured through Gross National Income (GNI) per capita, using a logarithmic scale to reflect the diminishing importance of income as it rises. The scores for the three dimension indices are aggregated into the single composite HDI score using a geometric mean.