The Human Development Index (HDI) is a composite indicator used to rank countries by level of human development. It takes into account measures of health (life expectancy), education (adult literacy and years of schooling), and income (GDP per capita) to provide a broader view of development than income alone. The Gender Development Index (GDI) is a related index that measures development based solely on female indicators to assess gender inequality. Calculating HDI and comparing scores across countries helps set development goals and identify areas for improvement within and between nations.