The long-term goal of the American Community Survey (ACS) is to produce more timely local area estimates. Currently, the only sources of Census Bureau local area income estimates are the decennial census (data only once every ten years) and the Small Area Income and Poverty Estimates (SAIPE) program (annual county and state estimates of median household income). The Census Bureau designed the battery of income questions as well as the edit and allocation specifications for the ACS to be as similar as possible to that of the Census in order to evaluate the ACS's performance. There are, of course, some differences inherent with the ACS that forced some changes. The purpose of this paper is to explain the major differences and provide a preliminary overview of the ACS results. This paper builds upon and updates a previous Census Bureau paper on this subject (Posey and Welniak 1999)

In Census 2000, a battery of eight detailed income questions and a total income question were posed to all persons 15 years old and over. The eight detailed income questions included (1) wages and salary, (2) self-employment income, (3) interest, dividend, and net royalty income, (4) Social Security, (5) Supplemental Security Income (SSI), (6) public assistance or welfare, (7) retirement, survivor, or disability income, and (8) any other sources of income received on a regular basis. These eight income questions were placed at the end of each set of person questions on the long form (sample) questionnaire so that response levels to the other less sensitive sample questions would not be adversely impacted. A "total income" question was first asked in the 1980 Census to aid in the resolution of income entry problems in the detailed questions. Both the 1990 and 2000 Census long form questionnaires also included the "total income" question. Test results indicated that a sizable number of all income recipients furnished responses to the total income question, but failed to provide answers to some or all parts of the detailed type of income questions, proving the total income item very important.

The biggest difference between collection methods in the ACS and Census 2000 is the income reference period. The ACS collects data throughout the year on an on-going, monthly basis. The ACS asks for a respondent’s income over the "past 12 months." The census, however, collected the income data for a fixed period of time – "during 1999" (the last calendar year.)