The American Community Survey (ACS) is a part of the U.S. Census Bureau's Decennial Census Program and is designed to provide more current demographic, social, economic, and housing estimates throughout the decade. The ACS provides information on more than 40 topics, including education, language ability, the foreign-born, marital status, migration and many more. Each year the survey randomly samples around 3.5 million addresses and produces statistics that cover 1-year, 3-year, and 5-year periods for geographic areas in the United States and Puerto Rico, ranging from neighborhoods to Congressional districts to the entire nation. For more information about the ACS, please visit our main page at: http://www.census.gov/acs. ACS tables are published on the Census Bureau's American FactFinder (AFF) website, http://factfinder2.census.gov, and are available for download in several forms. This document will brief data users on the contents of the ACS Summary File and explain how they can use it to obtain statistics.

The American Community Survey Summary File (ACSSF) is a unique data product that includes all the estimates and margins of error from the Detailed Tables and geographies that are published for the ACS. Other ACS data products, such as Subject Tables and Data Profiles, are created from the Detailed Tables and are therefore not available in the ACS Summary File.

Since the Detailed Tables contain a large number of cells, the tables are stored in a series of files with only the data from the tables, without such information as the title of the tables, the description of the rows, and the names of the geographic areas. That information is in other files that the user must merge with the data files to reproduce the tables.

The ACS Summary File data files are in American Standard Code for Information Interchange (ASCII) format. The files are divided into three types:

• Geographies - (position based and comma delimited)
• Geographies - (position based and comma delimited)
• Margins of Error - (comma delimited)

Chapter 2 discusses each component in detail and explains how to put them all together.

Data contained in the ACS Summary File cover demographic, social, economic, and housing subject areas. All Detailed Tables for the ACS 1-year, 3-year, and 5-year estimates are in the Summary File and are listed in Appendix A for their respective data release.

The published ACS Summary File geographies cover areas that are based on summary levels. A summary level specifies the content and the hierarchical relationships of the geographic elements that are required to tabulate and summarize data. For example, summary level code 040 represents the U.S. states, Washington D.C., and Puerto Rico; while summary level code 050 represents counties and county equivalents within states.

The ACS 1-year estimates are published for areas that have passed the 65,000 population threshold, while the ACS 3-year estimates are published for areas that have passed the 20,000 population threshold. The ACS 5-year estimates are published for all areas and include additional summary levels such as census tracts and block groups, and additional information for geographies such as American Indian areas, core based statistical areas, combined statistical areas, Congressional districts and state legislative districts. View the full list of summary levels published for the Detailed Tables in Appendix B. For the first time in the 2009-2013 ACS 5-year data release, data for census block groups are published in American FactFinder, as well as the ACS Summary File. The list of tables in the 5-year Appendix A shows which tables are available at the block group level.

Many resources are available to help users understand the ACS geographic terms and concepts. For additional information, please visit the Geography Reference page at http://www.census.gov/geo/www/reference.html and the Geography and the ACS page at http://www.census.gov/acs/www/guidance_for_data_users/geography/.

Since using the ACS Summary File can be challenging, users should first check if their tables of interest are available for download on American FactFinder. Below are some other options to help users retrieve the tables they want. They are listed in order based on ease of use. You can access these tools on the ACS Summary File page at http://www.census.gov/acs/www/data_documentation/summary_file/.

• Summary File Retrieval Tool

The Summary File Retrieval Tool is a macro-driven Excel spreadsheet that provides a method to easily retrieve a table for the nation, states, and all of the geographic areas in a state (or for all cross-state geographic areas such as metropolitan statistical areas or census regions). This tool is designed to be easy to use, and does not require any programming experience. There is a drop down menu from which the user can select the state for the table and receive data for all geographies within the state. One key requirement is that Microsoft Excel 2007 or later is needed. Other hardware and software requirements for the tool are listed on the ACS Summary File page.

• Summary File Excel Import Tool

The Summary File Excel Import Tool is a replicate of the Excel templates that Census 2000 provided for the Summary File 3 release. The Excel Import Tool provides a basic layout of each sequence in Excel in the same format as the estimate and margin of error files are formatted. For individuals that do not have Excel 2007 or later and are unable to use the Summary File Retrieval Tool, the Excel Import Tool provides an alternative option to read the ACS Summary File into Excel. You can access instructions for using this tool on the ACS Summary File page.

• SAS Programs

There are two programming options for SAS users. The first option is a set of individual SAS programs, one for each summary file by geography and sequence. These programs are best for users only interested in looking at a specific sequence for a specific geography. The second option is a single SAS program that is parameterized to allow users to read in any sequence for any geography into SAS. This program can also be used to read the entire summary file into SAS, and is designed for users looking for a large amount of data. You can access these programs on the ACS Summary File page.

• Summary File DataFerrett Tool (5-year release only)

DataFerrett is a tool provided by the Census Bureau to help users view, download, and manipulate a wide variety of data sets to suit their needs. Among the features provided by this tool is the ability to construct user-defined variables from the variables on the input data file(s), the ability for users to exclude data that is not of interest, a variety of options for downloading data, and the ability to create complex tabular reports from the data including graphs and thematic maps. This tool is ideal for data users who wish to view, customize, and restrict the data that is available in the ACS 5-year Summary File. A link to this tool is available on the Summary File page.

Here are some notable changes for the 2013 ACS Summary Files:

• New Layout for the ACS Summary File Technical Document

This year, we created one core technical document for the 2013 ACS 1-year, 2011-2013 ACS 3-year, and 2009-2013 ACS 5-year data releases with separate appendices specific to each release. Appendices E and F from earlier years are now Appendices A and B for the 2013 data releases. In addition, worked examples from previous technical documents are now available on the ACS Summary File page at http://www.census.gov/acs/www/data_documentation/summary_file/. Let us know what you think by sending your feedback to acso.users.support@census.gov.

• Format Change for Sequence Number Table Number Lookup Files

In previous years, we released the Sequence Number and Table Number Lookup Files in xls, sas7bdat, and txt formats. This year, we released the files in two formats: xls and sas7bdat.

• Block Groups Now Available in American FactFinder

For the first time with the 2009-2013 ACS 5-year data release, data for census block groups are published in American FactFinder, as well as the ACS Summary File. Block group level data for earlier years are only available in the ACS Summary File.

You can learn more about accessing block group level data using the ACS Summary File Retrieval Tool by viewing a video on the ACS Summary File page at http://www.census.gov/acs/www/data_documentation/summary_file/.

• TIGER/Line Shapefiles Pre-Joined with ACS Estimates Available

Did you know that TIGER/Line Shapefiles are available pre-joined with ACS 5-year estimates in geodatabase format? You can access these files on the TIGER Products page at http://www.census.gov/geo/maps-data/data/tiger-data.html

• Summary Level 080 Removed

Beginning with the 2009-2013 ACS 5-year data release, we will no longer produce estimates for summary level 080: State-County-County Subdivision-Place/Remainder-Census Tract. Summary level 080 estimates are for portions of tracts that are the intersecting areas of county subdivisions and places, or portions of county subdivisions and places that are the intersecting areas with tracts. We will continue to produce Census tract level estimates (summary level 140: State-County-Census Tract).

• Two additional areas included in the 2009-2013 ACS 5-Year Summary File

The 2009-2013 ACS 5-Year Summary File contains two areas from summary level 070: State-County-County Subdivision-Place/Remainder that are not available on American FactFinder. These geographies are "Louisville city (part), Louisville Central CCD, Jefferson County, Kentucky" and "Louisville city (part), Louisville West CCD, Jefferson County, Kentucky."

Please send any technical questions or comments on the ACS Summary File you have via email to: acso.users.support@census.gov. If you have questions or comments about the American Community Survey, you can submit a question online at ask.census.gov/.