The document discusses human development and metrics used to measure it such as the Human Development Index (HDI) and Inequality-Adjusted Human Development Index (IHDI). It explains that HDI measures a nation's health, education, and income levels while IHDI adjusts for inequality. According to the document, Norway currently ranks first in HDI while Sierra Leone ranks last. It also notes that Mexico ranks 77th in HDI based on its life expectancy, education, and income metrics.