Social SciencesDemographySociologyFamily DemographySocial DemographySocial InequalityHousehold EconomicsIncome DistributionIncome MeasurementInequalityPovertyGini Coefficient AnalysisHousehold Income DistributionHousehold Income InequalityIncome ConcentrationIncome Inequality HistoryIncome Inequality Measurement
The Census Bureau has been studying the distribution of income since the late 1940’s. The first income inequality statistics were published for families and came from the annual demographic supplement to the Current Population Survey (CPS). The most commonly used measure of income inequality, the Gini index (also known as the index of income concentration),1 indicated a decline in family income inequality of 7.4 percent from 1947 to 1968. Since 1968, there has been an increase in income inequality, reaching its 1947 level in 1982 and increasing further since then. The increase was 16.1 percent from 1968 to 1992 and 22.4 percent from 1968 to 1994 (see figure 1).2