But what about the ACS

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But what about the ACS?
What is the American Community Survey?
Replacement of the Long Form Continuous Survey
Methodology Conducted Monthly
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According to the Census Bureau The ACS is

• A large, continuous demographic survey
• Produces annual and multi-year estimates of the
  characteristics of the population and housing
• Produces characteristics, not a population count
• Produces information for small areas including
  tracts, block groups and population subgroups -
  updated every year
• Key component of reengineered 2010 census

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ACS Facts
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!
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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
and training Census takers
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How does the ACS work?
Three Methods of Data Collection
1. Mail Self-administered mail-out/mail-back
2. Telephone Computer Assisted
Telephone Interviewing (CATI) 3.
Personal Visits Computer Assisted Personal
Interviewing (CAPI) 13
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When will it start?
It already has
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American Community Survey Data Release Timetable
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Aug. 2010
In August of 2006 you got 2005 data
Aug. 2008
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Aug. 2008
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Aug. 2010
2010
April 1 August
Dec. (PL 94-171)
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Main differences between Census Long Form and ACS
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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 parents
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.
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Mail back rates from Minority populations are
significantly lowerSource C2SS test
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Different Non Response Follow-up rates based on
mail back returns

• l That is, in areas with low mail- back
  returns, a higher NRFU rate will be implemented
• l Thus, standard errors will be more
  consistent across neighborhoods

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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.
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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?
90 Confidence
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Chapter 8 Accuracy of the Data Estimate
Standard Errors Adjust for Survey Design
Factors - Table C
http//www.census.gov/prod/cen2000/doc/sf3.pdf
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Things to consider when trying to compare ACS
directly to Decennial data
Seasonality 12 months instead of "April 1")
(different jobs and workers, especially in
summer Group Quarters currently not in 2005 ACS
Non-response follow-up differences Data
collection period ACS is very long, compared to
very short in decennial Sample Sizes and MOEs
ACS is about 1 in 40 households compared to about
1 in 6
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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
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Within-Year Data Release Schedule for 2005 Data
August 15, 2006 Demographic and Social
Characteristics 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
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August 15th Demographic and Social
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August 29th Economic Characteristics
and PUMS too
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October 3rd Housing ---- Etcetera
i.e. Workplace Tables
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October 3rd Etcetera
For Workplace Geography
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November 14 Selected Population Profiles
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Where do I get ACS?
FactFinder
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There is a lot here
Even built in significance tests
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Note difference between DC and NJ
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A place to start mining ACS
Go to Detailed Tables
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Check out all the Tabs
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Pick Your Geography
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State . . .
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Places . . .
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Then Tables . . .
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Note the Tabs
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Keyword Search
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B and C Tables
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Full Table PASSED FILTERING
Statistically too Small
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Collapsed Table
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You Can Also Download the Results
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Download Options . . .
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My Selection
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What I took home
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Brand New CTPP Data Product
ACS CTPP Data Profiles
1. Resident Person Information
2. Resident Household Characteristics
3. Worker/Workplace Data
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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
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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
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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
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On-going concerns about ACS

• Will the sample be sufficient for small
  geographic area reporting? Will tract and BG and
  TAZ reporting occur after 60 months of data
  collection?
• Will Congress continue to fund the survey
  continuously, especially if CB asks for
  increasing budgets to meet the sample size
  requirements? (or will CB decrease the sample
  size, resulting in loss of small area
  tabulation?) Group Quarters

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What Were the Transportation Concerns in 2005?

• Will there be flow data? Flows are in serious
  jeopardy due to thresholds and disclosure
  proofing?
• Will there be a CTPP like package? Who will
  organize it, negotiate with the CB and contract
  with the CB. Timing of release? Cost?
• Will there be TAZs? How might they change, what
  tables will be available, for what geographies?

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Consolidated CTPP Purchase
AASHTO SCOP Census Data Work Group CTPP Technical
Group
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Current Expectations

• Will there be flow data? Flows are in serious
  jeopardy due to thresholds and disclosure
  proofing?
• Will there be a CTPP like package? Who will
  organize it, negotiate with the CB and contract
  with the CB. Timing of release? Cost?
• Will there be TAZs? How might they change, what
  tables will be available, for what geographies?

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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
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Census Data for Transportation Planning Preparing
for the Future Irvine, California May 11-13,
2005
http//www.trb.org/conferences/censusdata
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Now lets go do some Statistical Significance
Testing!