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American Communtiy Survey

FAQs developed by SANDAG on ACS


Board of Directors

Agenda item no. 05-04-6

April 22, 2005


FAQs developed by SANDAG on ACS

By Kristen Rohanna, San Diego Association of Governments


For more than 200 years, the Census Bureau has conducted a census every 10 years to collect population, housing, and socio-economic data from the public. The American Community Survey (ACS) is a new process that the Census Bureau will be using to collect this information. A key benefit of the ACS is that information about the region's residents will now be available every year rather than once every 10 years. As one of five Regional Census Data Centers in California, SANDAG recognizes the importance of the ACS, and we are working with the Census Bureau to ensure maximum participation by the region's residents. This report discusses the key aspects of the ACS and provides answers to questions that you and your constituents may have about it.

The importance of the census cannot be overstated. While the U.S. Constitution mandates a census be held every ten years for the purposes of Congressional reapportionment and legislative redistricting, the data is used for many other important purposes. For example, local jurisdictions use the data to determine where population loss or growth has occurred to better plan for their future. Community-based organizations use census data to target services and to apply for grants. SANDAG uses census data to analyze travel and other characteristics of the region's residents. The Census also anchors SANDAG's current estimates and forecasts, which are used throughout our work program activities and extensively by our member agencies, the public, and others.

Past decennial censuses used both short form and long form questionnaires. The short form was sent to every household in the United States and counts relatively few population characteristics such as race, Hispanic origin, and age. The long form was sent to a representative sample of 1 in 6 households and provided data on characteristics such as income, poverty, housing type, educational attainment, occupation, and travel patterns. The ACS will collect information currently on the long form, while every decade the short form will still be used for reapportionment and redistricting purposes. Even though the ACS is a new process, it is still part of the official census, and participation in the ACS is mandated by law.


The Census Bureau began testing the ACS to ensure its reliability in the late 1990s and full implementation of the ACS began in January 2005. Monthly, about one out of 480 households nationwide will receive a questionnaire (or 3 million annually).This means that roughly 27,000 households in San Diego County will receive the survey annually. No household will be selected more than once within five years, and the sampling procedures used in the ACS will mean that demographic, socio-economic, and housing data will be available every year rather than every ten years.The initial timing of the release of data depends upon the population size of a geographic area. Annual updates will occur every year after the first release (see the table below.) The availability of up-to-date data will be beneficial, because it will better reflect the changing characteristics of the region. More up-to-date information will help local agencies and community-based organizations secure federal and state funds for local projects, along with assisting in planning efforts.

Initial CS Data Releases Depend on Size of Area

Graph showing Type of Data, Population Size of Area, and year spans. Annual estimates 250,000+ 2003-2010 based on ACS testing. Annual Estimates 65,000+, 2006-2010. 3-year averages, 20,000+, 2008-2010. 5-year averages, Census Tract and Block Group, 2010.

Since the ACS is an on-going effort, it is critical that Congress adequately fund the ACS so that continuous, comprehensive data can be collected. In FY 2005, the Census Bureau asked for $165 million for the program, but received only $144 million. That amount was enough to begin full implementation of the program, but it was not sufficient to fund the surveying of group quarters (military barracks, nursing homes, college dormitories, etc.). President Bush's budget is requesting $169.9 million for FY 2006, which if appropriated, will provide for the inclusion of group quarters. A letter of support for the ACS from the SANDAG Board was sent to our federal delegation in November 2004.

Public awareness of the ACS will be another key element to its success. Unlike the decennial census that has a large-scale public information campaign, the ACS is not well-known. As noted above, a household has only a small chance of being included in the sample each month; therefore, someone may get selected who does not know of anyone else that received the survey form. Local jurisdiction officials may receive calls from concerned residents about the legitimacy of the form. It is important to encourage residents to complete the survey - better participation will lead to better data. Additional information, including a handbook for local officials regarding the ACS, can be found at, and responses to commonly asked questions are shown below.

Responses to Common Questions

1. What is this American Community Survey (ACS) all about?

This ACS is part of the census. It is a new approach being used by the Census Bureau to collect data about the characteristics of the population throughout the decade rather than once every 10 years.

2. Do I have to answer all of these questions?

Yes. You should answer all of the questions. The survey is part of the census, and answering it is required by law (Title 13, U.S. Code). Give your best estimate for items that ask for detailed amounts. Your answers are anonymous.

3. What happens if I don't complete the questionnaire and mail it back?

The Census Bureau will contact you, perhaps numerous times, by telephone or personal visit.

4. Why was I selected for this survey when none of my neighbors were?

The Census Bureau selects a random sample of addresses (not people). Any address has about 1 chance in 480 of being selected in any month. No household will receive an ACS questionnaire more often than once every five years.

5. How do I know that the information I give will not be used improperly?

The Census Bureau will protect the confidentiality of your information. Federal law sets a high fine and imprisonment for any Census Bureau employee who gives your personal data to anyone inside or outside the government.

6. How will my community benefit by having data from this survey?

Your community will receive federal funds based on this information for schools, roads, senior centers, and other services. The use of up-to-date data means that areas with growth will have more adequate funding.

Executive Director

Key Staff Contact: Kristen Rohanna; (619) 699-6918;

No Budget Impact

Updated: 6/6/2012
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