American Community Survey

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American Community Survey

• Idaho State Data Center
• Boise
• September 7, 2005

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What is the American Community Survey?

• A large, continuous demographic survey
• Produces annual and multi-year estimates of the
  characteristics of the population and housing
• Produces characteristics, not a population count
• Produces information for small areas including
  tracts, block groups and population subgroups -
  updated every year
• Key component of reengineered 2010 census

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What is the American Community Survey?

• A program to provide annual and multi-year data
  for communities
• Age, gender, race/ethnicity
• Families, children, elderly
• Income, poverty
• Work, unemployment
• Housing
• Education

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Effects of the American Community Survey (ACS)
on the 2010 Census

• Eliminate long-form
• Conduct a short form only census
• Better knowledge of local areas
• Ongoing contacts with local governments
• Cost savings

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How will the American Community Survey help your
community?

• Establish community goals
• Compare your community with others
• Identify community problems and solutions
• Measure and publicize program results
• Increase government accountability
• Ensure fair funding distribution
• Create community-specific programs
• Locate facilities and programs

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Expansion to Full ACS Sample

• Testing and development 1996-2004
• Full expansion began in 2005
• Group quarters delayed until 2006
• Annual national sample of about 3 million
  addresses
• Provide profiles every year for communities of
  65,000 or more
• Provide 3- to 5-year cumulations for communities
  of less than 65,000 population

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American Community Survey Data Release Timetable
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Comparing ACS with the Decennial Census Sample

• How do the samples compare?
• How does data collection compare?
• What is the impact on the data?

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How do the samples compare?

• Similarities
• Systematic samples of MAF (Master Address File)
  addresses
• Differential sampling rates for areas based on
  population size

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Sampling Rates
Governmental Unit Size Number of Occupied Housing Units Census 2000 Sampling Rates ACS 5-year Sampling Rates
0 - 200 50.0 50.0
201 - 800 50.0 35.0
801 - 1200 25.0 17.5
1201 - 2000 16.7 12.0
Over 2000 12.5 8.5
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How do the samples compare?

• Differences ACS Sample Design
• Initial sampling rate
• about 2.5 each year
• about 12.5 over 5-year period
• Results in an initial sample of about
• 250,000 addresses each month
• 3 million addresses each year
• 15 million addresses over 5-year period

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How do the samples compare?

• Differences
• ACS samples every year and spreads sample over 12
  months census samples once a decade and uses the
  entire sample at the same time
• ACS subsamples for personal visit follow-up
  court ruled against census subsampling
• Census sample estimates based on about 18 million
  housing units ACS 5 year estimates based on
  about 11 million housing units

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How does data collection compare?

• Similarities
• Primary method is self-response to a paper
  questionnaire
• Content is the same

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How does data collection compare?

• ACS data collection procedures
• Mail
• Telephone
• Personal visits
• Use a current residence rule

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How does data collection compare?

• Differences
• ACS nonresponse follow-up uses computer-assisted
  telephone and computer-assisted personal
  interviews past censuses have used only paper
  questionnaires
• ACS data collected only from household members
  census data often collected from neighbors
• ACS interviews conducted by experienced and
  well-supervised staff census enumerations
  conducted by inexperienced temporary workforce

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What is the impact on the data?

• ACS estimates have higher sampling error
• measures are released for each estimate and shown
  as 90 confidence limits or margins of error in
  every table
• Similar sampling error measures for census long
  form sample estimates have not been provided

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What is the impact on the data?

• ACS estimates have lower potential nonsampling
  error
• Unit nonresponse no data for a case
• Item nonresponse data missing for an item
• These and other measures are released on ACSs
  Quality Measures website
• www.census.gov/acs/www/UseData/sse/index.htm

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Unit Response
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Multi-year Estimation

• Most multi-year estimates are generated by
  computing an average based on combining each
  years estimates
• Estimates are computed using the geography in
  place as of the most recent year of the period
• Dollar valued data items are inflation adjusted
  to most recent year of the period

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Multi-year Estimation Medians

• Medians are produced using combined data records
  from all years, not by averaging each years
  median
• A 3-year median household income estimate is
  determined by combining the household records
  from the 3 years into one data set and
  determining the median from this combined
  distribution

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Multi-year Estimates

• Example
• Item with year-to-year increases and decreases
• Overview only
• Focus is on the timing and creation of 3-year and
  5-year data products

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Multi-year Estimates
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ACS Data Products

• Data Profiles
• Multi-Year Profiles
• Narrative Profiles
• Expanded Ranking Tables
• Redesigned and expanded Detailed Tables/Base
  Tables
• Public Use Microdata Sample Files (PUMS)
• New Subject Tables
• New Selected Population Profiles
• New Thematic Maps

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ACS Data Products
American FactFinder http//factfinder.census.gov
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ACS Data Products
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Data Profiles
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Narrative Profile
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Multi-Year Profiles
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Ranking Tables
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Ranking Table(without statistical significance)
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Ranking Table (with statistical significance)
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Ranking Table (chart)
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Thematic Map
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Subject Table
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Selected Population Profile
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Detailed Table/Base Table
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2004 ACS Products by Geography Type
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Outreach and Education Materials

• State and local handbook
• National and community organizations handbook
• Congressional toolkit
• American Indian/Alaska Native toolkit
• ACS Data User Guide (Fall 2005)

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Information about the American Community Survey
www.census.gov/acs/www
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Guide to the ACS Data Products
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For More Information
American Community Survey Web site
(www.census.gov/acs/www)
Call us at 1-888-456-7215
E-mail us at cmo.acs_at_census.gov
Subscribe to the ACS Alert
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U. S. Census BureauSeattle Regional Office

• Partnership and Data Services
• Cam McIntosh, Information Specialist
• U.S. Census Bureau
• 700 Fifth Avenue, Suite 5100
• Seattle, WA 98104
• cam.mcintosh_at_census.gov
• 800-233-3308
• 206-553-5836