<Table> <Tr> <Td> Highest 25% Above median </Td> <Td> Below median Lowest 25% </Td> <Td> Data unavailable </Td> </Tr> </Table> <Tr> <Td> Highest 25% Above median </Td> <Td> Below median Lowest 25% </Td> <Td> Data unavailable </Td> </Tr> <P> The Human Development Index (HDI) is a composite statistic (composite index) of life expectancy, education, and per capita income indicators, which are used to rank countries into four tiers of human development . A country scores higher HDI when the lifespan is higher, the education level is higher, and the GDP per capita is higher . The HDI was developed by Pakistani economist Mahbub ul Haq which was further used to measure the country's development by the United Nations Development Program (UNDP). </P> <P> The 2010 Human Development Report introduced an Inequality - adjusted Human Development Index (IHDI). While the simple HDI remains useful, it stated that "the IHDI is the actual level of human development (accounting for inequality)", and "the HDI can be viewed as an index of' potential' human development (or the maximum IHDI that could be achieved if there were no inequality)". </P>

Explain the meaning of hdi. mention three components of measuring hdi