Infant mortality is a measure of the number of infants who die before reaching their first birthday. Infant mortality rates tell how many babies die each year for every thousand babies that are born. Because the rates reflect the well-being of the most dependent members of a society, they are often interpreted as a measure of how well the society is able to take care of its people. For this reason, comparing infant mortality rates of different nations or communities is a way of evaluating a society's standard of living.