This document discusses the concept and calculation of the Human Development Index (HDI). It begins by explaining that HDI is a statistical tool used by the UNDP to measure a country's social and economic development based on health, education, and standard of living. It then provides details on how HDI is calculated using indices for life expectancy, education, and gross national income. Examples are given to demonstrate how to calculate HDI scores for a country like India using available data. The document concludes by noting the importance of HDI in measuring and comparing development between nations.