Data Collection

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American Community Survey Overview
Jerry Wong Information Services Specialist Los
Angeles Regional Office U.S. Census Bureau

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What is the American Community Survey?

• A large, continuous survey that
• is sent to 3 million resident addresses per year
• produces characteristics of population and
  housing
• produces estimates for small areas and small
  population groups
• Produces characteristics, not a population count
• Key component of the decennial census program

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History and Timeline of the ACS
Congress renewed interest in an alternative to
the once-a-decade census
First operational test conducted in 4 sites
N866,000 housing units in 1,239 counties
First 1-yr estimates released for areas 65,000
Continuous measurement conceptualized
N165,000 housing units
2009
1981
1990
1994
2006
2005
2000
1999
1995
2008
Work began on what evolved into the ACS
Test sites expanded yearly to 36 counties in 26
states
Group Quarters added
N3,000,000 housing units in all counties in 50
states, DC PR
First 3-yr estimates released for areas 20,000
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Developing the ACS

• The ACS was developed to
• Focus the Census on improving the population
  count
• Provide characteristic data more than once every
  10 years to frame policy issues
• Allow use of current data to respond to new trends

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Decennial Census

• Census 2000 used 2 forms
• short form asked for basic demographic and
  housing information, such as age, sex, race, how
  many people lived in the housing unit, and if the
  housing unit was owned or rented by the resident
• long form collected the same information as
  the short form but also collected more in-depth
  information such as income, education, and
  language spoken at home
• Only a small portion of the population, called a
  sample, received the long form.

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Census 2000 and ACSSimilarities

• Many questions similar
• Many of the same basic statistics are released
• Comparisons can be made for most population and
  housing subjects
• http//www.census.gov/acs/www/UseData/compACS.html
  
• 5-year estimates will be produced for same broad
  set of geographic areas
• including census tracts and block groups, zip
  code tabulation areas

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Census 2000 and ACSKey Differences

• ACS data now available for larger and mid-sized
  areas
• ACS data for small geographic areas and
  population groups will be produced every year
  starting in 2010
• ACS data describe a period of time and published
  data are based on 12 months, 36 months, or 60
  months

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Census 2000 and ACSData Quality

• Goal of the ACS Produce data of comparable
  quality to Census 2000 long form
• ACS 5-year data
• Sampling error is larger in ACS due to smaller
  sample size
• Non-sampling error is smaller due to
• Lower rate of nonresponse
• Higher item response rates
• Permanent interviewing staff using automated data
  collection

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2010 Census and the ACS
2010 Census ACS
U.S. population count U.S. population characteristics
Short form only Includes short form questions
Only long form is for U.S. territories, except Puerto Rico Conducted in Puerto Rico
Usual residence rule Current residence rule
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American Community SurveyContent
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Social Characteristics

• Education
• Marital Status
• Fertility
• Grandparent Caregivers
• Veterans
• Disability
• Status

• Place of Birth
• Citizenship
• Year of Entry
• Language Spoken at Home
• Ancestry/Tribal
• Affiliation

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Economic Characteristics

• Income
• Benefits
• Employment Status
• Occupation
• Industry
• Commuting to Work
• Place of Work

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Housing Characteristics

• Tenure (own vs. rent)
• Occupancy Structure
• Housing Value
• Taxes Insurance
• Utilities
• Mortgage/Monthly Rent

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Demographic Characteristics

• Sex
• Age
• Race
• Hispanic Origin

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Recent Content Changes

• New Content
• 2008
• Health Insurance Coverage
• Veterans Service-connected Disability
• Marital History
• 2009
• Field of Undergraduate Degree
• Wording and format changes in 2008 to match
  Census 2010 questions

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2008 Content Changes

• Three new questions
• Health Insurance Coverage
• Veterans Service-connected Disability
• Marital History
• Deletion of one question
• Time and main reason for staying at the address
• Changes in some wording and format

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ACS Sample Design

• Sample is accumulated over TIME to produce lowest
  levels of geographic detail to replace census
  sample
• 5 years of data are required for areas and
  population groups with less than 20,000
  population
• Sample cases selected from an updated Master
  Address File (MAF)

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Sample

• Questionnaires mailed to about 1 in 480 addresses
  each month throughout the U.S. and Puerto Rico.
• 1 in 40 addresses per year (2.5 of the
  population).
• Average of 500-600 addresses per month per
  congressional district.
• Total of 3 million addresses each year, or
  250,000 per month.
• Inclusion of population in group quarters
  beginning in 2006.

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Target Population

• Resident population of the United States and
  Puerto Rico
• Living in housing units and group quarters (group
  quarters added in 2006)
• Current residents at the selected address

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Methodology

• Sample includes about 3 million addresses each
  year
• Three modes of data collection
• mail
• phone
• personal visit
• Data are collected
  continuously throughout
  the year

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Operations
Mail Telephone Personal Visit
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Period Estimates

• Describe the average characteristics over a
  specific period of time
• Contrast with point-in-time estimates
• Do not describe the characteristics on a
  specific date
• Period is 1 year, 3 years, or 5 years for ACS

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Geographic Boundaries

• Multiyear estimates are based on geographic
  boundaries as of January 1 of the last year in
  the multiyear period
• Example 2006-2008 ACS estimates use
• boundaries as of Jan 1,
  2008
• Boundaries of other statistical areas will be
  updated every decade in conjunction with the
  decennial census
• 2010 Census boundaries will be used for data
  released in 2011

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ACS Data Release Schedule
Hypothetical situation If Census 2010 contained
a long form, detailed characteristic data would
not be available until 2012
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ACS Data Products

• Profiles
• Data Profiles
• Narrative Profiles
• Comparison Profiles
• Selected Population Profiles
• Tables
• Detailed Tables and Collapsed Tables
• Subject Tables
• Ranking Tables
• Geographic Comparison Tables
• Thematic Maps
• Public Use Microdata Sample (PUMS) Files

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ACS Data for Geographic Areas in Hawaii
Geography 2008 1-Year Data 65,000 Population 2006-2008 3-Year Data 20,000 Population
State Hawaii Hawaii Hawaii In various metro or micropolitan statistic areas Hawaii Urban Hawaii Rural
County Hawaii County Honolulu County Maui County Hawaii County Honolulu County Maui County Kauai County
Place Honolulu CDP Honolulu CDP Hilo CDP Kahului CDP Kailua CDP Kaneohe CDP Kihei CDP Mililani Town CDP Pearl City CDP Waimalu CDP Waipahu CDP
School District Hawaii Department of Education Hawaii Department of Education
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ACS Data for Geographic Areas in Hawaii
Geography 2008 1-Year Data 65,000 Population 2006-2008 3-Year Data 20,000 Population
Metropolitan or Micropolitan Statistical Area Hilo, HI Micropolitan Statistical Area Honolulu Metropolitan Statistical Area Kahului-Wailuku, HI Micropolitan Statistical Area Hilo, HI Micropolitan Statistical Area Honolulu Metropolitan Statistical Area Kahului-Wailuku, HI Micropolitan Statistical Area Kapaa, HI Micropolitan Statistical Area
Urban Area Honolulu, HI Urbanized Area Kailua (Honolulu Co.)Kaneohe, HI Urbanized Area Honolulu, HI Urbanized Area Kailua (Honolulu Co.)--Kaneohe, HI Urbanized Area Hilo, HI Urban Cluster Kahului HI Urban Cluster Kailua (Hawaii Co.)--Holualoa, HI Urban Cluster Kihei, HI Urban Cluster PukalaniMakawaoHaikuPauwela, HI Urban Cluster
Congressional District Congressional District 1 Congressional District 2 Congressional District 1 Congressional District 2
Public Use Microdata Area (PUMA) PUMA5 00100, PUMA5 00200, PUMA5 00301, PUMA5 00302, PUMA5 00303, PUMA5 00304, PUMA5 00305, PUMA5 00306, PUMA5 00307 PUMA5 00100, PUMA5 00200, PUMA5 00301, PUMA5 00302, PUMA5 00303, PUMA5 00304, PUMA5 00305, PUMA5 00306, PUMA5 00307
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Using the DataFactors to Consider

• Universe and residence rules
• Time Periods
• Reference Periods

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Residence Rules

• The American Community Survey uses a
• two-month rule
• Decennial census based upon the concept of
• usual residence

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Residence Rules

• Resident of a housing unit if a person
• - Lives there year round
• - Lives there more than 2 months but not
  year round
• - Is living there now with no other place to
  live
• - Is away now for 2 months or less
• Not a resident of a housing unit if a
  
• person
• - Lives there 2 months or less with another
• residence
• - Is away now for more than 2 months

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Period Estimates

• Describes the characteristics of an area
• over a specific period of time
• Contrasts with point-in-time estimates
• that describe the characteristics of an
• area on a specific date
• 1-year, 3-year, and 5-year estimates are
  
  released for
  geographic areas that meet specific population
  thresholds

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Reference Periods

• ACS uses the interview date as the
• single reference point, or as the end of
• a reference period, for all data collection.

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Questions With No Specific Reference Period

• Most ACS questions
• do not stipulate a
• period of time that
• should be referenced
• Interpretation is yearly
• average since the
• data are collected
• each month and
• averaged across months

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Questions With a Specific Reference Period
Relative to Interview Date

• Other questions specify a period of time
  relative to
• the date of interview
• Interpretation is still a
• yearly average but
• covering a slightly
• different period of time
• than the calendar year

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Group Quarters

• Place where people live or stay that is
  normally
• owned or managed by an entity or organization
  
• providing housing or services for the
  residents.
• Two types of group quarters
• 1. Institutional
• 2. Non-institutional
• Group Quarters Population includes all people
  not
• living in households.
• - This term includes those people
  residing in group
• quarters as of the date the ACS was
  conducted.

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Overview of ACS Timeline

• First year of data collection for full sample in
  2005.
• Data for calendar year 2007 released beginning in
  August 2008.
• Annual data for geographic areas over 65,000
  population.
• 3 year averages are now available for geographic
  areas 20,000 to 65,000.
• 5 year averages for geographic areas under 20,000
  in 2010.

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Timeline

• ACS Data single year collection (e.g. 2007) is
  closed out just after the beginning of a calendar
  year (e.g. 2008)
• Single-year and multiyear data products start to
  become available in the summer of the same year.
• For example 2007 ACS estimates were released in
  2008
• The cycle repeats EVERY year

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Release Schedule for ACS Data
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Understanding Estimates and Margin of Error
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Estimates

• ACS data are estimates
• ACS data are not counts of the population or
  housing
• Population counts are produced from the decennial
  census
• - Counts are updated throughout the decade
  through the Population Estimates Program

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Margin of Error (MOE)

• Margin of Error Definition
• A measure of the precision of an estimate at
  a given level of confidence (90, 95, 99)
• MOEs at the 90 confidence level for all
  published ACS estimates
• Confidence Interval Definition
• A range that is expected to contain the
  population value of the characteristic with a
  known probability.

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Margin of Error
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Interpreting Margin of Error

• Indicates that a data user can be 90 percent
  certain that the estimate and the population
  value differ by no more than the value of the MOE
• MOE can help data users assess the reliability of
  an estimate
• MOE can help data users avoid misinterpreting
  small differences between estimates as significant

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American Community Survey Multiyear Data
2008

2006
2007
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Population Thresholds for ACS Estimates
1-year estimates 3-year estimates 5-year estimates
65,000 people X X X
20,000 people X X
Less than 20,000 people X
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Constructing Multiyear Estimates

• Data are pooled across 36 or 60 months
• Data are weighted to produce estimates
• Estimates are controlled for age, sex, race, and
  Hispanic origin
• Multiyear estimates are not an average of 1-year
  estimates

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Use Multiyear Estimates When

• No 1-year estimate is available
• Margins of error for 1-year estimates are larger
  than required
• Analyzing data for small population groups

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Currency vs. Reliability
Currency Reliability
1-year estimates provide information based on the last year Larger sample sizes produce estimates that are more statistically reliable
3-year estimates provide information based on the last year and the 2 years before that 3-year estimates are based on 3 times as many sample cases as 1-year estimates
5-year estimates provide information based on the last year and the 4 years prior 5-year estimates are based on 5 times as many sample cases as 1-year estimates
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Inflation Adjustment

• Dollar-valued data items are inflation adjusted
  to the most recent year for the period
• Income, rent, home value, and energy costs
• Adjusted using inflation factors based on the
  Consumer Price Index (CPI)
• Adjustment designed to put the data into dollars
  with equal purchasing power

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Geographic Boundaries

• Multiyear estimates are based on geographic
  boundaries as of January 1 of the last year in
  the multiyear period
• Boundary Annexation Survey collects boundary
  changes
• Boundaries of other statistical areas will be
  updated every decade in conjunction with the
  decennial census

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Population Controls

• Estimates of housing units and people are
  controlled to the population estimates derived
  from the Population Estimates Program
• Multiyear estimates are controlled to the average
  of the individual years estimates for the period

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Using multiyear Estimates to Make Comparisons?
Comparing Across Geographies

• Only compare the same type of estimate
• 1-year estimates to other 1-year estimates
• 3-year estimates to other 3-year estimates
• 5-year estimates to other 5-year estimates
• Same time period

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Comparing Across Time Periods

• Same geographic area
• Use caution if geographic boundaries have changed
  over time
• Easier to compare non-overlapping periods
• Make comparisons using the same length time period

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Overlapping Periods
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American Community Survey Learning More

• ACS Main Page
• 2008 Data Release Page
• 2006-2008 Data Product Details
• Guidance on Comparing 2008 ACS 1-Year Data
• Guidance on Comparing 2006-2008 ACS 3-Year Data
  to Other Sources
• Geographic Overview
• User Notes
• Errata Sheets
• Design and Methodology Report
• The ACS Compass Products

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American Community Survey Accessing Home Page
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American Community SurveyACS Main Page
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American Community Survey 2008 Data Release
http//www.census.gov/acs/www/Products/
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American Community Survey 2006-2008 Data Product
Details
http//www.census.gov/acs/www/Products/users_guide
/
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American Community Survey 2006-2008 Data Product
Details - Hawaii
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American Community Survey Geography Overview
http//www.census.gov/acs/www/UseData/geo.htm
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American Community Survey Comparing 2008 ACS
1-Year Data
http//www.census.gov/acs/www/UseData/compACS2008.
htm
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American Community Survey Comparing 2006-2008
ACS 3-Year
http//www.census.gov/acs/www/UseData/compACS2006-
2008.htm
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American Community Survey User Notes
http//www.census.gov/acs/www/UseData/usernotes.ht
m
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American Community Survey Errata

http//www.census.gov/acs/www/UseData/Errata.htm
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American Community Survey Subject Definitions
http//www.census.gov/acs/www/UseData/Def.htm
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American Community Survey Using Multiyear
Estimates
http//www.census.gov/acs/www/UseData/myeoverview.
html
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American Community Survey Question by Question
Fact Sheet
http//www.census.gov/acs/www/SBasics/SQuest/facts
heet.htm
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American Community Survey Question by Question
Fact Sheet Health Insurance
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American Community Survey Design and Methodology
Report

• Important reference document covering methods
  used in producing ACS data

Available at http//www.census.gov/acs/www/SBasics
/desgn_meth.htm
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The ACS Compass ProductsA Compass for
Understanding and Using American Community Survey
Data

• General Data Users
• Businesses
• High School Teachers
• Congress
• Federal Agencies
• Media
• PUMS
• State and Local Governments
• Puerto Rico Community Survey (PRCS)

• Researchers
• Rural Areas
• American Indian and Alaska Native Populations
• Planned
• Puerto Rico Community Survey (PRCS) in Spanish

http//www.census.gov/acs/www/UseData/Compass/comp
ass_series.html
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The ACS Compass ProductsA Compass for
Understanding and Using American Community Survey
Data

• Fully scripted PowerPoint presentations
• An Overview of the ACS
• Things that May Affect the Estimates
• Understanding Multiyear Estimates
• Data Products
• Geographic Areas and Concepts
• Introduction to the PUMS files
• E-learning ACS Tutorial (forthcoming)

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For more information

• Subscribe to ACS Alert
• http//www.census.gov/acs/www/Special/Alerts.htm
• Visit the ACS/PRCS website
• http//www.census.gov/acs/www
• Contact by telephone
• 301-763-1405
• Contact by email
• acso.users.support_at_census.gov

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Resources Need Assistance?
U.S. Census Bureau Partnership Data Services
Program 15350 Sherman Way, Suite 400 Van Nuys, CA
91406 [phone] Toll Free
L.A. Regional Website www.census.gov/losangeles
laro.isp-partnership_at_census.gov
Jerry.B.Wong_at_census.gov
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