Where do data for HDI come from?
Life expectancy at birth is provided by the UN Department of Economic and Social Affairs; mean years of schooling by Barro and Lee (2010); expected years of schooling by the UNESCO Institute for Statistics; and GNI per capita by the World Bank and the International Monetary Fund. For few countries, mean years of schooling are estimated from nationally representative household surveys. Many data gaps still exist in even some very basic areas of human development indicators. While actively advocating for the improvement of human development data, as a principle and for practical reasons, the Human Development Report Office does not collect data directly from countries or make estimates to fill these data gaps in the Report.