Documentation: ACS 2006 -- 2010 (5-Year Estimates)
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Publisher: U.S. Census Bureau
Document: Design and Methodology: American Community Survey
citation:
Social Explorer; U.S. Census Bureau; Design and Methodology, American Community Survey. U.S. Government Printing Office, Washington, DC, 2009.
Design and Methodology: American Community Survey
Chapter 14. Data Dissemination
Overview
This chapter deals with the 1-year and 3-year data products. Future versions of this document will include a discussion of the 5-year data products. The American Community Survey (ACS) data products and supporting documentation are released in several series and at several Internet locations. The primary Web site for data dissemination is the American FactFinder (AFF); supporting documentation can be found on the ACS Web site and the Census Bureau's File Transfer Protocol (FTP) site.

Since 2000, the ACS has been tabulating and publishing single year estimates for specific areas with populations of 250,000 or more. In 2005, the ACS expanded its sample size to cover all of the United States and the Commonwealth of Puerto Rico. In summer 2006, the ACS started releasing data annually for areas with populations of 65,000 or more. In 2008, the ACS is releasing 3-year period estimates for areas with a population of 20,000 or more on an annual basis. For smaller areas, it will take 5 years to accumulate a large enough sample to produce releasable estimates. Once those data are collected, the Census Bureau will release tabulations annually, based on 5-year period data for areas as small as census tracts and block groups.

Federal agencies distribute billions of dollars among states, tribal governments, and population groups, based on social and economic data. In the past, the statistics that determined services locations and program funding came in large part from the long-form sample of the decennial census. As the ACS continues to grow, its data products will provide updated versions of many of the long-form products from Census 2000. Beginning in 2010, the decennial census no longer will include a long-form sample, and ACS data products will provide high-quality, updated annual statistics for comparisons of the demographic, social, economic, and housing characteristics of areas and population groups. The ACS statistics also will show trends and relative differences between areas and population groups. These data products will continue to meet the needs of those who previously used the decennial census sample statistics, and will provide more current statistics than those available from the census long-form sample, which reflect only one point in time.

Schedule
Data Release Timetable
By 2010, the information on social, demographic, economic, and housing characteristics previously available only once every 10 years will be available annually through the ACS for all areas. Each year thereafter, these areas will get new estimates based on the 5-year interval ending in the latest completed sample year.

Figure 14.1 summarizes the data products release schedule. In 2006, the first set of 1-year estimates was released for specific areas with populations of 65,000 and more. These areas will continue to receive 1-year estimates annually. In 2008, data collected over a 3-year period (2005− 2007) was released for areas with at least 20,000 people. These areas will continue to receive 3-year estimates annually. In 2010, the first 5-year products will be released based on data collected in 2005−2009. These products will be produced for areas down to census tracts and block groups. Once 3- and 5-year products are produced, annual updates will follow, as indicated by Table 14.1.arThe AFF Web site contains data maps, tables, and reports from a variety of censuses and surveys.
AFF lists these data sets by program areas and survey years. AFF contains data for a wide variety
of surveys including the Decennial Census, the ACS, the Population Estimates Program, the Economic
Census, and the Annual Economic Surveys.

Data product Population threshold Year of data release
2006 2007 2008 2009 2010 2011 2012 2013
1-year estimates 65,000+ 2005 2006 2007 2008 2009 2010 2011 2012
3-year estimates 20,000+     2005- 2006- 2007- 2008- 2009- 2010-
        2007 2008 2009 2010 2011 2012
5-year estimates All areas*         2005- 2006- 2007- 2008-
            2009 2010 2011 2012

* All legal, administrative, and statistical geographic areas down to the tract and block group level.

Presentation of Tables
American FactFinder
The AFF Web site contains data maps, tables, and reports from a variety of censuses and surveys. AFF lists these data sets by program areas and survey years. AFF contains data for a wide variety of surveys including the Decennial Census, the ACS, the Population Estimates Program, the Economic Census, and the Annual Economic Surveys.

The AFF is the primary Web access tool for ACS data. Data products include detailed tables, data profiles, comparison profiles (1-year data only), narrative profiles, ranking tables and charts (single year data only), geographic comparison tables, thematic maps, subject tables, selected population profiles, and downloadable public use microdata sample (PUMS) files.

ACS Web Site
The ACS Web site contains a wealth of information, documentation, and research papers about ACS. The site contains important metadata, including more than 50 population concept definitions and more than 40 housing concept definitions. The ACS Web site can be found at .

Documentation on the accuracy of the data also is included, and provides information about the sample design, confidentiality, sampling error, nonsampling error, and estimation methodology. The errata section lists updates made to the data. The geography section gives a brief explanation of the Census Bureau's geographic hierarchy, common terms, and specific geographic areas presented.

File Transfer Protocol (FTP) Site
The FTP site is intended for advanced users of census and ACS data. This site provides quick access to users who need to begin their analyses immediately upon data release. The data are downloaded into Excel, PDF, or text files. Users of the FTP site can import the files into the spreadsheet/database software of their choice for data analysis and table presentation. Documentation describing the layout of the site in the README file is available in the main directory on the FTP server. The FTP site can be accessed through the ACS Web site.