The American Community Survey: An Overview
by the Pennsylvania State Data Center
Volume 1, Number 1 September 1999
What is the American Community Survey?
The ACS is a method of collecting data at local levels between Decennial Censuses.
Currently, the Decennial Census is the only data and uniform measure from the national
level to the block level. Unfortunately, the data becomes outdated after a few years but
must still be used since they are the most comprehensive data available.
The ACS is still in the test and implementation phase. The goal is to have the ACS replace
the long form used in the Decennial Census. Then every ten years, only the short form
would need to be completed by U.S. residents during the Decennial. The rich socio-economic
data that results from the long form would be refreshed each year by the ACS.
How is it Conducted?
Four test sites were introduced in 1996: Bravard County, FL; Multnomah County, OR;
Rockland County, NY; and Fulton County, PA. Additional counties were added each year.
Schuylkill County, PA was added in 1999. A comparison of data with the 2000 Decennial
Census will be conducted and results analyzed. Full implementation in every county of the
nation is expected by 2003. The sample size will be 3 million households annually.
Each month a systematic sample of addresses from the most current MAF is selected. The
sample does not contain addresses contacted in the previous five years. Therefore,
residents only answer the ACS at the most once every five years. The sample size is
designed to approximate the sampling ratio of the 2000 Decennial with over sampling in
smaller governmental areas.
The ACS uses the Master Address File for mailing or delivering monthly questionnaires to
potential respondents. Six weeks after the mailing, commercial phone listings are used for
non-response follow-up, conducting the interview on the telephone in lieu of a completed
form. Follow-up is finished by doing personal visits to a subsample of those who still
have not responded.
Address Updating is an ongoing operation using the Master Address File and updating it
through visits of Census Field staff to the community governments to identify new
addresses or make corrections. Local lists are utilized wherever possible. Postal Service
lists are also integrated.
Data Collected
The ACS uses the annual average population throughout the year. For small-area estimates,
the average is for a multi-year period. Areas with populations of 65,000 or more will use
annual averages when fully implemented. Areas with populations of 30,000 to 64,999 will
use two year averages; those with populations of 20,000 to 29,999 use three year averages;
those with a 15,000 to 19,999 population size use four year averages; and all places less
than 15,000 use five year averages.
Once in full operation, data will be available every year for areas and population groups
of 65,000 or more beginning in 2004. For areas of population of 15,000 or less, it will
take five years to accumulate a large enough sample to provide estimates with accuracy
similar to the decennial census. That means that updated information for areas such as
neighborhoods will be available starting in 2008 and then every year thereafter.
Current residence rules apply to the ACS. People who are staying for two or more months at
a temporary location are included at that location.
Types of data that will be collected and tabulated include: age, gender, race/ethnicity,
family structure, income, poverty, education, work, unemployment, commuting patterns, and
housing characteristics.
All individual data is confidential and protected by Title 13. Participation in the ACS,
like the Decennial, is mandatory.
Funding
Continuous measurement also means continuous funding. The only way this ACS can be
successful is with sufficient funding by Congress to conduct it each year.
Why It is Important
As with the Decennial Census, data are used as a part of funding formulas for billions of
federal and state government monies to local communities. The data will help communities
make decisions about where to locate infrastructure, encourage economic development, and
measure the performance of programs. It will be used in the formulation, administration
and evaluation of public policy.
The ACS will be used in the same ways that Decennial Census data has been used. The
difference is that the data will always be current, an invaluable characteristics in the
decision making process.