Are you looking for community data
from the American Community Survey?
This tutorial will show you an easy way
to access block group level data using the American Community
Survey Summary File Retrieval Tool.
Block groups are the lowest level
of geography published in the ACS.
They contain a minimum of 600 people or 240 housing units
and a maximum of 3,000 people or 1,200 housing units.
Many kinds of data users, including local governments,
emergency planners, and non-profit organizations,
use block group estimates from the ACS
to help determine community needs.
The Census Bureau is often the only source of statistics
at the local level every year,
giving even the smallest communities accurate,
timely information that is essential for decision-making.
Block group level estimates,
as well as census tract level estimates, are only available
in the ACS 5-year datasets.
These levels of geography are not available
in the ACS 1-year or 3-year datasets.
While tracts are available
through the Census Bureau's data access tool,
American FactFinder, block groups are only available
in the ACS 5-year Summary File.
The ACS Summary File is a set of comma-delimited text files
that contain all of the Detailed Tables.
The Detailed Tables are stored in a series of files
on the File Transfer Protocol (or FTP) site.
These files contain only the data from the tables;
they do not contain such information as the table title,
description of the rows, or geographic identifiers.
The ACS Summary File shows data that have already been tabulated
for specific geographic areas.
If you are unsure about navigating the FTP site,
the Summary File Retrieval Tool is a great resource for you.
This tool allows users to load tables from the ACS Summary File
into an Excel spreadsheet, then sort or manipulate it as needed.
Please note that you must have Excel 2007 or newer
to run this tool, and it is recommended
that you close all other applications before starting.
The retrieval tool allows you to access all the tracts
and block groups per table per state, so this tool is ideal
if you are interested in a few states.
If you are interested in all of the tracts and block groups
for the nation, you may want to go directly to the FTP site.
Let's begin by accessing the American Community Survey main
page at www.census.gov/acs.
From there, click on the "Data & Documentation" tab at the top
of the page, then click on "Summary File."
This is the Summary File page.
You can find links to many useful resources,
including the files on the FTP site
and the technical documentation.
Not all tables are available at the block group level,
so before you open the retrieval tool,
review the 5-year Technical Document for table availability.
You can access this document by clicking on the
"5-Year Tech Document" link.
Let's say that you are interested
in finding poverty estimates for block groups.
After you open the 5-Year Tech Document, go to Appendix E.
From here, scroll down to the poverty tables.
The table number starts with B17,
and the table numbers are the same as the tables
in American FactFinder.
A "Yes" in the column "Table Available
for Block Groups on Summary File?"
indicates that a table is available
at the block group level.
You can see that only selected tables are available
for this geography.
For this example, we will use Table B17017 "Poverty Status
in the Past 12 Months by Household Type
By Age of Householder."
Now that you know your table number, we can find your table
at the block group level using the retrieval tool.
Use the back button in your internet browser to return
to the Summary file page.
Under "Tools for using the ACS Summary File," click on the
"Summary File Retrieval Tool" link.
You will have the option to open or save the file.
Here, we opened it with WinZip.
When your zip program opens, double click
on the Summary File Retrieval Tool Excel
macro-enabled worksheet.
You may need to enable macros by clicking "Enable Content" in the
"Security Warning" bar.
Then, click on the application button at the top of the page
to start the data retrieval tool.
In Step 1, you are prompted to select a state and data product.
We will use Illinois as our state,
and the 2007-2011 ACS 5-year estimates as our data product.
After making those selections, click "Next."
Step 1 may take a few moments to run
as lookup tables are created.
In Step 2, you are prompted to select your desired table either
by table ID or table description.
We know that we want to use Table B17017,
so we will choose the radio button next
to "Select by Table ID."
Next, we will use the "Table Name by ID" drop-down menu
to select Table B17017.
Because we are interested in estimates at low levels
of geography, we will select the checkbox next to "Tracts
and Block Groups ONLY."
There is also a checkbox next to "Merge Estimates with Margin
of Errors," but it will take more time to run the program
if you make this selection.
Now, click "Next" to begin downloading and importing data.
You can follow the progress of the retrieval tool
by monitoring the bar
at the bottom left corner of the spreadsheet.
When operations are complete, you will see a pop up box appear
on your screen stating "Operation Complete
for product year 2011 for selected 5 year data product."
Click "OK."
Now you have estimates for Table B17017 for all tracts
and block groups in Illinois.
You can see that there are 2,176 households in Census Tract 101,
Cook County, Illinois.
Of these households, 616 have income
in the past 12 months below poverty level.
As you keep scrolling, you also see estimates for block groups.
There are 3 block groups within Census Tract 101
for Cook County-block groups 1, 2, and 3.
As an example, Block Group 1 has 310 households,
and 72 of these households have income
in the past 12 months below poverty level.
If you are interested in the corresponding margin of error
for these estimates, click on the "MarginOfError" tab
at the bottom of the spreadsheet.
The estimates in the ACS Summary File are the same
as the pre-tabulated tables in American FactFinder (or AFF).
Table B17017 for Census Tract 101, Cook County,
Illinois shows the same estimates
as we viewed in the Summary File.
Remember, block group level estimates are only available
in the ACS Summary File, not American FactFinder.
When you are ready to reset the worksheet
and start a new search, click the reset button
at the top of the page.
This concludes our tutorial on accessing community level data
with the American Community Survey Summary File
Retrieval Tool.
Learn more about the American Community Survey
on our website, census.gov/acs.
If you have further questions about the ACS,
contact our call center at 1-800-923-8282
or submit a question at ask.census.gov.
The U.S. Census Bureau...measuring the nation's
people, places, and economy.