"To create statistics about income, assistance, earnings, and poverty status. Local, state, tribal, and federal agencies use our published income data to plan and fund programs that provide economic assistance for populations in need." They can also determine the distribution of social assistance and services. https://www.census.gov/acs/www/about/why-we-ask-each-question/income/

Survey, via mail to specific addresses

3.5 million addresses nationwide are randomly selected each year to respond to the American Community Survey. The sample size indicated below applies to the nationwide size, housing units selected for final interviews.

"Data are based on a sample and are subject to sampling variability. The degree of uncertainty for an estimate arising from sampling variability is represented through the use of a margin of error. The value shown here is the 90 percent margin of error. The margin of error can be interpreted roughly as providing a 90 percent probability that the interval defined by the estimate minus the margin of error and the estimate plus the margin of error (the lower and upper confidence bounds) contains the true value. In addition to sampling variability, the ACS estimates are subject to nonsampling error (for a discussion of nonsampling variability, see ACS Technical Documentation). The effect of nonsampling error is not represented in these tables."

The data is used by various tribal and government agencies to fund programs and services for households that qualify for assistance.