But what about the ACS?. What is the American Community Survey?. Replacement of the Long Form Continuous Survey Methodology Conducted Monthly. According to the Census Bureau The ACS is…. A large, continuous demographic survey
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But what about the ACS?
What is the American Community Survey?
Replacement of the Long Form
Continuous Survey Methodology
A large, continuous demographic survey
About 1 in 40 Households Sampled per year
250,000 Households Sampled per month
Same Transportation questions as 2000 Long Form
Decennial Long Form is History, Kaput, Gone!
But why change and have an ACS?
Eliminate the Census Long Form for 2010 and Thereafter
Eliminate the peak in Congressional funding
Eliminate the peak in hiring andtraining Census takers
How does the ACS work?
Three Methods of Data Collection
1. MailSelf-administered mail-out/mail-back
2. TelephoneComputer Assisted Telephone Interviewing (CATI)
3. Personal VisitsComputer Assisted Personal Interviewing (CAPI) 1:3
When will it start?
It already has
In August of 2006 you got 2005 data
April 1 August Dec. (PL 94-171)
Main differences between Census Long Form and ACS
Some Emerging Issues
People might be counted twice, e.g. once at summer cabin and once at a “permanent home”. Or once at university and once at parent’s home.
Areas with seasonal populations, e.g. due to “snow bird” migration, and due to school enrollments, with housing occupancy that varies from 95% to 40% might show up as 80%.
lThat is, in areas with low mail-back returns, a higher NRFU rate will be implemented
lThus, standard errors will be more consistent across neighborhoods
Understanding Sample Error
Sample Error is larger because the number of census forms collected each year are smaller.
Changes of plus or minus 2% may be due to Sample Error and do not reflect measurable change.
Comparing ACS directly to 2000 Data can be iffy
Statistical Significance Tests
Standard Error = Margin of Error / 1.65
But what about MOEs for 2000 data?
Chapter 8: Accuracy of the Data
Estimate Standard Errors
Adjust for Survey Design Factors - Table C
Things to consider when trying to compare ACS directly to Decennial data
Seasonality12 months instead of "April 1") (different jobs and workers, especially in summer
Group Quarterscurrently not in 2005 ACS
Data collection periodACS is very long, compared to very short in decennial
Sample Sizes and MOEsACS is about 1 in 40 households compared to about 1 in 6
Data Release Schedule
1-year data in 2006 (every year thereafter)
3-year data in 2008 (every year thereafter)
5-year data in 2009 (every year thereafter)
Plus the within-year release schedules
Within-Year Data Release Schedule for 2005 Data
August 15, 2006
Demographic and SocialCharacteristics
August 29, 2006
Economic Characteristics; Public Use Microdata File
October 3, 2006
Housing Characteristics; Narrative Profiles; Workplace Base Tables
November 14, 2006
Selected Population Profiles
August 15th Demographic and Social
August 29th Economic Characteristics
and PUMS too
October 3rd Housing ---- Etcetera
i.e. Workplace Tables
October 3rd Etcetera
… For Workplace Geography
November 14 Selected Population Profiles
Where do I get ACS?
There is a lot here
Even built in significance tests
Note difference between DC and NJ
A place to start mining ACS
Go to Detailed Tables
Check out all the Tabs
Pick Your Geography
State . . .
Places . . .
Then Tables . . .
Note the Tabs
“B” and “C” Tables
Full Table – PASSED FILTERING
Statistically too Small
You Can Also Download the Results
Download Options . . .
What I took home
CTPP Data Product
ACS CTPP Data Profiles
1. Resident Person Information
2. Resident Household Characteristics
3. Worker/Workplace Data
Resident Person Information for…
States, Large Cities, MSAs
Florida Statewide data
Mode to work
Travel Time to work
Departure Time for work
Mode to work by Travel Time
Mode to work by Average Travel Time
Resident Household Characteristics for..
The Nation, States, All PUMAs,
Counties and Places over 65k
Wisconsin Statewide data
Mode to work by Vehicles Available
Vehicles Available in Households
Household Size by Vehicles Available
Vehicles Available by Workers in Household
Persons in Households by Workers in Household
Worker / Workplace Data for…
States, Counties and
Places over 65k
Total Workers -- Travel Time to work -- Mode to Work
Get ACS CTPP Data Profiles online or from the Class Workbook CD
AASHTO SCOPCensus Data Work Group
CTPP Technical Group
ACS related activities currently underway
NCHRP 8-48 Guidebook Using the American Community Survey Data for Transportation Planning ($350K) Expected May 2007
NCHRP 8-36 Project Disclosure Avoidance Techniques to Improve ACS Data($75) Expected Next Year
Census Geography and Participant Statistical Areas Program — Hoping to have TAZs included
ACS Use Capacity Building Peer Exchange, SCOP Working Group/FHWA, Spring 2007
Census Data for Transportation Planning
Preparing for the Future
May 11-13, 2005
Now let’s go do some
Statistical Significance Testing!