There are many differences between the ACS and the CPS ASEC. Some of the most significant are:

• The ACS uses an up-to-date sampling frame (the Census Bureau’s Master Address File updated by using the U.S. Postal Service’s Delivery Sequence File and targeted address canvassing). Prior to 2014, the CPS ASEC used sampling frames derived once a decade from the Decennial Census (updated with new construction). Beginning in 2014, the CPS sample is derived annually from the Master Address File with updates from the United States Postal Service (USPS). Overall coverage for the ACS and the CPS ASEC appear to be comparable.
• The ACS data collection methodology is substantially different from the CPS ASEC, as the CPS ASEC is conducted by interviewers via Computer Assisted Telephone Interviewing (CATI) or Computer Assisted Phone Interviewing (CAPI). In contrast, the ACS uses a self-response mail-out/mail-back questionnaire with an internet response option, followed by CATI or CAPI follow-up conducted by interviewers. Additionally, the ACS, like the decennial long form, is mandatory, and therefore response at the unit and item level is higher in the ACS than the CPS ASEC.
• The income questions in the ACS cover the major income sources, while the CPS ASEC income questions are much more detailed and provide more comprehensive coverage of all potential income sources.
• The time period for ACS income estimates is different than the time period used by the CPS ASEC and Census 2000. The latter two use the previous calendar year as the reference period while the ACS asks about income in the previous twelve months using a rolling sample each month.
• Until 2006 the ACS had excluded group quarters from its sampling frame, slightly affecting the estimates of income and poverty, as some people in the poverty universe are in non-institutional group quarters, such as those in group homes and shelters. The ACS began including both institutional and non-institutional group quarters in its sampling frame starting in January 2006 while the CPS ASEC includes only non-institutional group quarters.

The American Community Survey (ACS) is currently the largest household survey in the United States. The ACS is part of the 2010 Decennial Census Program and will eliminate the need for a long-form sample questionnaire. The ACS offers broad, comprehensive information on social, economic, and housing data and is designed to provide this information at many levels of geography, particularly for local communities. With full implementation in 2005, the ACS is now producing annual estimates for geographic areas with populations of 65,000 or more. From 2008 to 2013, the ACS released data for geographic areas with populations between 20,000 and 64,999 using data collected over three-year periods. In 2010, the ACS began using five-year averages to provide estimates for all areas down to census tracts/block groups.

Because of its detailed questionnaire and its experienced interviewing staff, the Current Population Survey (CPS) Annual Social and Economic Supplement (ASEC) is a high quality source of information used to produce the official annual estimate of poverty, and estimates of a number of other socioeconomic and demographic characteristics, including income, health insurance coverage, school enrollment, marital status, and family structure.

The following charts summarize the key differences between the ACS and the CPS for both Income and Poverty: