This document discusses the Human Development Index (HDI), which is a composite index used to rank countries by level of "human development" based on indicators of health, education, and income. It provides background on the HDI, explaining that it aims to assess development by focusing on people's capabilities and freedom rather than just economic growth. The document then outlines how the HDI is calculated using fixed minimum and maximum values for life expectancy, education, and income indicators. It acknowledges some limitations of the HDI in only focusing on a few dimensions and not capturing intra-country variations or short-term changes.