American Community Survey

Presented at the Meeting of the National Neighborhood Indicators Partnership

Susan SchechterMay 2010

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What I’ll Cover

Introduction to the American Community Survey

Census 2000 and ACS – Similarities and Differences

Plans for the first release of ACS 5-year estimates

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Introduction to the ACS

The 2010 Census will only collect critical data required of the full population

The detailed demographic, social, economic, and housing data will now be collected and disseminated using the American Community Survey

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Introduction to the ACS

While ACS content is similar to the Census 2000 long form, the design and methodology differ

ACS data are collected continuously throughout the year and estimates are released once-a-year in the form of 1-year, 3-year, and 5-year aggregates

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Introduction to the ACS

The ACS has a diverse set of data users including federal, state, and local governments, academia, media, and the private sector

Uses range from a single estimate for a grant application or homework assignment to complex research using microdata files

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Census 2000 and ACSSimilarities

Census 2000 questions are on the ACS

ACS produces many of the same tables and characteristics as Census 2000

Same broad set of geographic areas

Same basic data dissemination vehicle – American FactFinder and same basic types of data products

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ACS Data Products Used in Census 2000

Detailed Tables Summary Files Data Profiles and Subject Tables (Similar to

Quick Tables)Thematic MapsGeographic Comparison TablesPublic Use Microdata Sample (PUMS) Files

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ACS Data Products Not Included in Census 2000

Narrative ProfilesRanking TablesComparison Profiles Selected Population Profiles

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Census 2000 and ACSKey Differences

ACS data are collected continuously and all ACS estimates are period estimates

Estimates will be released every year rather than once-a-decade

ACS estimates are released in the form of both single year and multiyear estimates

ACS estimates have more sampling error

Period Estimates

Describe the average characteristics over a specific period of time

Contrast with point-in-time estimates – ACS estimates do not describe the characteristics

as of a specific date

Period is 1 year, 3 years, or 5 years for ACS

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ACS estimates will be released every year while

census estimates were released only once-a-decade

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ACS estimates are released in the form of both single year and multiyear estimates based on the

estimated population of the geographic area

ACS Data Release Schedule

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Data Product Population Size Data released in:

of Area 2006 2007 2008 2009 2010 2011 2012

1-Year Estimates 65,000+ 2005 2006 2007 2008 2009 2010 2011

for Data Collected in:

3-Year Estimates 20,000+ 2005-2007 2006-2008 2007-2009 2008-2010 2009-2011

for Data Collected in:

5-Year Estimates All Areas* 2005-2009 2006-2010 2007-2011

for Data Collected in:

Data Product Population Size Data released in:

of Area 2006 2007 2008 2009 2010 2011 2012

1-Year Estimates 65,000+ 2005 2006 2007 2008 2009 2010 2011

for Data Collected in:

3-Year Estimates 20,000+ 2005-2007 2006-2008 2007-2009 2008-2010 2009-2011

for Data Collected in:

5-Year Estimates All Areas* 2005-2009 2006-2010 2007-2011

for Data Collected in:

* Five-year estimates will be available for areas as small as census tracts and block groups.Source: US Census Bureau* Five-year estimates will be available for areas as small as census tracts and block groups.Source: US Census Bureau

Hypothetical situation: If Census 2010 contained a long form, detailed characteristic data would not be available until 2012

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Data Release Rules

Estimated Population of Geographic Area

Type of ACS Estimates Released

65,000 or more 1-year, 3-year, and 5-year

20,000 to 64,999 3-year, and 5-year

Less than 20,000 5-year

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Example 1: Percent Foreign Born Population Areas with 65,000+ population

2005 2006 2007 2008 2009 2010

Single-year estimates 20.0 21.2 23.3 28.6 32.6 35.1

3-year estimates (2005 – 2007) 21.5

3-year estimates (2006 – 2008) 24.8

3-year estimates (2007 – 2009) 28.6

5-year estimates (2005 – 2009) 25.9

3-year estimates (2008 – 2010) 32.2

5-year estimates (2006 – 2010) 28.9

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Example 1: Percent Foreign Born Population Areas with population between 20,000 and 65,000

2005 2006 2007 2008 2009 2010

3-year estimates (2005 – 2007) 21.5

3-year estimates (2006 – 2008) 24.8

3-year estimates (2007 – 2009) 28.6

5-year estimates (2005 – 2009) 25.9

3-year estimates (2008 – 2010) 32.2

5-year estimates (2006 – 2010) 28.9

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Example 1: Percent Foreign Born Population Areas with less than 20,000 population

2005 2006 2007 2008 2009 2010

5-year estimates (2005 – 2009) 25.9

5-year estimates (2006 – 2010) 28.9

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The ACS sample is smaller than the sample in Census

2000 which means that ACS estimates will include more

sampling error

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Quality of ACS Estimates

Recent research suggests that margins of error around ACS 5-year estimates will be about 1.75 times as large as those associated with the Census 2000 sample estimates

Evaluations after Census 2000 demonstrated reductions in ACS nonsampling error relative to Census 2000

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ACS Displays Margins of Error

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Census 2000 and ACSOther Differences

ACS includes a few revisions to question wording as compared with Census 2000

ACS has added several new questions that were not included in Census 2000

ACS reference periods and residence rules differ from those used in Census 2000

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Questions Added to the ACS

Health Insurance Coverage

Marital History

Service-Connected Disability Status and Rating

Field of Degree

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Residence Rules

Both the census and the ACS describe the resident population (housing units and group quarters) in the United States and Puerto Rico

Census 2000 - usual residence as of April 1, 2000

ACS – current residence as of interview date

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Reference PeriodsCensus 2000 centers its count and age distributions on

a reference date of April 1, 2000. Some questions have a reference period different than April 1. Data generally describe characteristics between March and June of 2000.

The ACS collects all data using a reference date of the date of interview. Like Census 2000, some questions have reference periods. Given that interviews are spread fairly evenly across the year, the data describe the calendar year but there is an overlap for questions that include a 12 month reference period.

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Differences between the 2010 Census and the ACS

The 2010 Census will count the population to support apportionment and redistricting

The ACS will supplement this information with annually updated data on the characteristics of population and housing

Plus, many of the same differences (residence rules, reference periods) when you compare Census 2000 long form data to ACS

2009 ACS

First release of ACS 5-year estimates– Data will be available for small areas

• Census tracts • Block Groups

– Will be based on data collected from 2005, 2006, 2007, 2008 and 2009

The 2009 ACS (1-year estimates) and the 2007-2009 ACS (3-year estimates) will also be released

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Census 2000Data Products from the Long Form Sample

Product Released

Summary File 3 (SF3) 2002 - 2003

Summary File 4 (SF4) 2003

American Indian and Alaska Native Summary File (AIAN SF)

2003

Public use microdata sample (PUMS) files

2003

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ACS Data Products1-Year and 3-Year Estimates

ACS data products have included detailed tables, other summary products and PUMS files

The geographic detail of SF3 as well as data comparable to the SF4 and the AIAN SF were not possible with 1-year and 3-year estimates

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ACS 5-Year Estimates

We plan to release the first ACS 5-year estimates this year

The 5-year data products will be similar in many ways to the existing ACS products and to Census 2000 products

Over time, we expect the specific set of data products to change as we receive input from users and evaluate usage

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ACS 5-Year EstimatesRelease Restrictions

Unlike the 1- and 3-year estimates, there will be no 5-year population thresholds and no table restrictions based on reliability

Only restrictions will be to protect the confidentiality of the data

Margins of error will be published with all ACS estimates

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ACS 5-Year EstimatesSet of Proposed Tables

We will produce the ACS tables that are most comparable to those released in Census 2000 Summary File 3

We will also produce some tables that were not included in Census 2000 – new tables that were designed after Census 2000

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ACS 5-Year EstimatesSet of Proposed Tables

Most proposed summary levels will receive a full set of 5-year tables regardless of size or type – exception is block groups

Some tables have geographic restrictions similar to those in place for Census 2000 SF3

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2005-2009 ACS Data Products Planned

Detailed tablesSummary filesData profilesNarrative profilesSubject tables

**No Selected Population Profiles for ACS 5-Year Data

**No SF4, or AIAN SF Files for the first release.

Geographic comparison tablesThematic mapsPUMS files

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ACS 5-Year EstimatesNumber of Geographic Summary Levels by

Data Product

Estimated number of geographic summary

levels

Detailed tables 670K

Data profiles 180K

Subject tables 170K

Geographic comparison tables, thematic maps

90K

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ACS 5-Year EstimatesNumber of Tables Proposed for Release

Estimated number of tables

Summary levels other than block

groups

Block Groups*

Detailed tables 800 330

Data profiles 4 0

Subject tables 60 0

Geographic comparison tables, thematic maps

90 0

* The total number of block groups is estimated to be about 210,000

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ACS 5-Year EstimatesGeographic Summary Levels

Most, but not all, of the geographic summary levels in Census 2000 SF3 will be included in the first ACS 5-year release

This includes tracts, block groups, geographic components, and geographic intersections

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ACS 5-Year EstimatesData Product Limitations by Geographic

Summary Level

For proposed geographic summary levels, we will always produce detailed tables

We will only produce data and narrative profiles, subject tables and geographic comparison tables for a subset

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ACS 5-Year EstimatesExamples of 5-year Geographic Summary

Levels for US and Puerto Rico

Residence-based

tabulations

Estimated number of areas

1-year 3-year 5-year

Congressional districts

435 435 435

Counties 785 1,030 3,221

Tracts 0 0 ~66,000

Block groups 0 0 ~ 210,000

All summary levels ~ 6,500 ~ 13,500 ~ 670,000

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ACS 5-year EstimatesData Dissemination Plan

We plan to release 5-year estimates annually and disseminate all 5-year ACS data products through the American FactFinder

We plan to release census block group data only in a summary file format, accessible from the American FactFinder download center

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ACS 5-Year EstimatesTentative Data Release Schedule

Type of estimate Release date

2009 ACS

1-year estimates

Sept 2010

2007-2009 ACS

3-year estimates

Dec 2010 or later, after the release of the 5-year estimates

2005-2009 ACS

5-year estimates

Nov or Dec 2010, some data products released in 2011

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ACS 5-Year EstimatesFuture Products

We are evaluating the disclosure avoidance issues related to producing annual 5-year PUMS files.

We plan to release the ACS SF4 and the ACS AIAN SF in 2012 based on the 2006-2010 ACS 5-year estimates

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ACS 5-Year EstimatesFuture Products

We expect to refine this plan for future releases and value your feedback on shortcomings or overkill

We will continue to look for the most effective way to release 3 sets of ACS estimates annually along with the production of SF3, SF4, and AIAN SF-like products and PUMS files

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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@census.gov