This report presents data on median household income and the Gini index of income inequality based on the 2014 and 2015 American Community Surveys (ACS). Estimates from the 2015 ACS show a significant increase in median household income at the national level and for 39 states.1 Median household income increased between 2014 and 2015 for 21 of the 25 most populous metropolitan areas.2 The Gini index was significantly higher in 2015 than 2014 for the United States and eight states. The ACS provides detailed estimates of demographic, social, economic, and housing characteristics for states, congressional districts, counties, places, and other localities every year. A description of the ACS is provided in the text box “What Is the American Community Survey?”3
The estimates contained in this report are primarily based on the 2014 and 2015 ACS. The ACS is conducted every month, with income data collected for the 12 months preceding the interview. Since the survey is continuous, adjacent ACS years have income reference months in common. Therefore, comparing the 2014 ACS with the 2015 ACS is not an exact comparison of the economic conditions in 2014 with those in 2015, and comparisons should be interpreted with care.4 For more information on the ACS sample design and other topics visit <www.census.gov/acs/www>.
1 The medians from this report were calculated from the microdata and household distributions using 2015 dollars. Inflation adjusting previous year published estimates using the CPI-U-RS will not match exactly to the estimates in this report.
2 Metropolitan and micropolitan statistical areas (metro and micro areas) are geographic entities delineated by the Office of Management and Budget (OMB) for use by federal statistical agencies in collecting, tabulating and publishing federal statistics. The term Core Based Statistical Area (CBSA) is a collective term for both metro and micro areas. A metro area contains a core urban area of 50,000 or more population, and a micro area contains an urban core of at least 10,000 (but less than 50,000) population. For more information see <www.census.gov/programs-surveys/metro-micro.html>.
3 The text of this report discusses data for the United States, including the 50 states and the District of Columbia. Data for the Commonwealth of Puerto Rico, collected with the Puerto Rico Community Survey, are shown in Table 1, Figure 1, and Figure 3.
4 For a discussion of this and related issues, see Howard Hogan, “Measuring Population Change Using the American Community Survey,” Applied Demography in the 21st Century, Steven H. Murdock and David A. Swanson, Springer Netherlands, 2008.