The Human Development Index across 184 countries, tracked from 1990 to 2023.
The Human Development Index combines life expectancy at birth, expected and mean years of schooling, and gross national income per capita into a single value between 0 and 1. Source: UNDP Human Development Report, via Our World in Data. UNDP classifies scores above 0.800 as very high human development, 0.700 to 0.799 as high, 0.550 to 0.699 as medium, and below 0.550 as low.
The HDI is a geometric mean of three dimension indices: a long and healthy life, measured by life expectancy at birth; knowledge, measured by expected and mean years of schooling; and a decent standard of living, measured by gross national income per capita on a logarithmic scale.
The logarithmic treatment of income is deliberate. It encodes the assumption of diminishing returns — that an additional thousand dollars matters far more at low income levels than at high ones. Without it, wealthy countries would dominate the Index entirely.
The geometric mean matters too. It means poor performance on any one dimension cannot be fully compensated by strong performance on the others. A country cannot buy its way to a high HDI while neglecting health or education.
The Index was created in 1990 by Mahbub ul Haq and Amartya Sen, explicitly as an alternative to judging development by GDP alone.
Small differences are not meaningful. Countries separated by a few thousandths are statistically indistinguishable. Rank changes at that scale reflect measurement noise rather than real divergence.
Trajectory carries more information than level. Hover any country to see its change since 1990. Some of the largest gains have come from countries starting at low bases, which the ranking obscures.
The Index says nothing about distribution. Two countries with identical HDI can have very different inequality. UNDP publishes an inequality-adjusted variant for this reason, and the gap between the two is often larger than the gap between countries.
It also says nothing about environmental cost. This is the Index’s most significant limitation for sustainability research. A country can raise its HDI through resource extraction and emissions-intensive growth, and the Index will record only the improvement. UNDP now publishes a planetary pressures-adjusted index alongside it, which reorders the ranking substantially.
HDI is most interesting when set against the environmental data on this site. A country scoring highly on human development while running a large ecological deficit has achieved that development on borrowed environmental capital.
Related work of mine on development and its environmental cost: