in addition data problems, some conceptual problems can arise when using per capita income as a measure of economic growth. One is that this measure tells us nothing about how output is distributed among the residents of a nation. During a period when a country's measured per capita output grew very rapidly, its poorest residents might have become even poorer.Therefore, when using the rate of increase in GDP per capita as growth measure,we must recognize that it tell us nothing about relative income of various groups within a country.