Inequality in human development across the globe

The Human Development Index is the world's most famous indicator of the level of development of societies. A disadvantage of this index is however, that only national values are available, whereas within many countries huge subnational variation exists in income, health and education. Here we present the Subnational Human Development Index (SHDI), which shows within-country variation in human development and its dimension indices for over 1600 regions within 160 countries. The newly observed variation is particularly strong in low and middle developed countries (home to 70% of the world population) but less important in the most developed ones. While education disparities explain most of the SHDI inequality within low-developed countries, income differences are increasingly responsible for SHDI inequality within more highly developed countries. The new SHDI opens the possibility of studying global socio-economic change with unprecedented coverage and detail, increasing the ability of policy-makers to monitor the Sustainable Development Goals