This report is one of a series produced to highlight results from the 2008 American Community Survey (ACS), focusing on changes between the 2007 ACS and the 2008 ACS. The report series is designed to cover a variety of economic topics, such as poverty, occupation, home values, and labor force participation. This series provides information about the changing economic characteristics of the nation and states, the District of Columbia, and Puerto Rico. The ACS also provides detailed estimates of demographic, social, economic, and housing characteristics for 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?”

This report presents data on household income at the national and state levels based on the 2007 ACS and 2008 ACS. Household income includes the income of the householder and all other people 15 years and older in the household, whether or not they are related to the householder. For comparisons of household income, this report focuses on the median—the point that divides the household income distribution into halves, one half with income above the median and the other with income below the median. The median is based on the income distribution of all house-holds, including those with no income.

In the 2008 ACS, information on income was collected between January and December 2008, and people were asked about income for the previous 12 months (the income reference period), yielding a total income time span covering 23 months (January 2007 to November 2008). Therefore, adjacent ACS years have income reference months in common, and comparing the 2008 ACS with the 2007 ACS estimates is not an exact comparison of the economic conditions in 2008 with those in 2007.

The data contained in this report are based on ACS samples that were selected for interview in 2007 and 2008 and are estimates of the actual figures that could have been obtained by interviewing the entire population using the same methodology. All comparisons presented in this report have taken sampling error into account and are significant at the 90 percent confidence level unless noted otherwise. Due to rounding, some details may not sum to totals. For information on sampling and estimation methods, confidentiality protection, and sampling and nonsampling errors, please see the “2008 ACS Accuracy of the Data” document located at <www2.census.gov/programs-surveys/acs/tech_docs/accuracy/accuracy2008.pdf>.