Bill--I would hope that folks take a "good hard look" at what is
happening with the ACS proposed standard products. The impact in the
loss of data is really a lot larger than one might expect. Over the
next few days I hope to look at and revisit some of the impact analysis
we did on many of these disclosure rules. While we looked at the rules
from the perspective of how they would affect our special 3-year
CTPP-like product, many of the new 5-year rules are exactly the same.
Which by the way are even more restrictive than the CTPP2000 rules.
As for what people should do we can ALL start by acting like the good
planners we are and help develop and provide the necessary information
and data to help inform and frame the debate/discussion. One important
thing is that we need to do, is to make sure that those who need to
know, and who use the data, know what they will be getting. Things have
certainly changed with the elimination of the decennial long form. I am
not sure if the people who need to know really realize (and understand)
what they will (or not) be getting.
In a broader sense there are some major policy questions lurking behind
all of this. For example, to satisfy the Title 13 confidentiality
requirements how much confidentiality protection is enough? We do know
that an absolute zero risk of disclosure would mean not releasing
anything. But how much risk can we accept? How close to zero does it
have to be? When AASHTO appealed the the rules for the 3-year CTPP-like
product an analysis done by Westat put the risk close to zero but that
was not acceptable. The Census Bureau has always maintained that the
law is clear on this but is it really?
The new Administration's policies seem to be
directed towards more openess and transparency with respect to federal information - in
many cases completely reversing the more restrictive policies imposed by the previous
Administration. Does this pose an opportunity to revive the questions/arguments made by
the CTPP users' community in opposition to the disclosure rules promulgated after the
2000 Census?
I don't particularly like the notion of more politicization for the Census Bureau,
but I like even less (especially as a small metro area) being denied access to
transportation planning data that accounts for the uniqueness of individual communities
and travel patterns. Perhaps if we again raised this issue starting now, we might get
some or all of the less restrictive rules restored before the 2010 Census begins and
certainly before the time that a full Census-based CTPP would become available.
Do others have any thoughts/opinions about such an approach?
Bill Moore, M.ITE, MPO Administrator
City of Pueblo - Urban Transportation Planning Division
PACOG MPO/TPR
223 N Santa Fe Avenue, Pueblo, CO 81003
Phone: 719-553-2945 FAX: 719-553-2950
E-mail: bmoore@pueblo.us<mailto:bmoore@pueblo.us> Web:
www.PACOG.net<http://www.pacog.net/>
-----Original Message-----
From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces@chrispy.net]On Behalf Of
Murakami, Elaine
Sent: Friday, March 06, 2009 10:38 AM
To: ctpp-news(a)chrispy.net
Subject: [CTPP] CB Federal Register Notice: ACS 5-year data products proposal
Dear Everyone:
Today, the Census Bureau issued this Federal Register notice. The 5-year ACS is the
first ACS product for small area geography, e.g. census tracts and block groups. I have
extracted KEY POINTS that will GREATLY IMPACT data availability for transportation tables
and result in a lot of DATA SUPPRESSION at the tract and block group level. As this FR
was just issued today, we have not had a chance to estimate the amount of suppression that
would occur given these proposed conditions.
We are currently working on profile sheets using the 2005-2007 ACS (3-year data) that was
released in December 2008. We are finding many tables to be suppressed. So, even with
the population threshold of 20,000 for the 3-year ACS data, there is considerable
suppression on the current ACS standard table production, at least those tables of key
interest to transportation planners.
As most of you know, the first CTPP using ACS is a planned 3-year accumulation from ACS
2006-2008. The table list will be re-submitted by AASHTO to the Census Bureau in a few
weeks.
The next CTPP product is envisioned as a 5-year accumulation from ACS 2006-2010. Because
of the many rules the CB has established to protect individual confidentiality not just
for the ACS Standard tables, but also for custom tabulations like the CTPP, we believe
that the 5-year CTPP for small area tabulation (e.g. TAZs) will need to rely on synthetic
data generated inside the CB using the ACS microdata records.
_________________________________________________________
*Federal Register Notice: The 5-Year ACS Data Products Release Plan
Today the U.S Census Bureau published its data release plan for the ACS 5-year data
products in the Federal Register (E9-4803). Beginning in late 2010, the Census Bureau
plans to introduce 5-year data products covering the January 2005 through December 2009
data collection period. The release of the 5-year estimates will achieve the goal of the
ACS to provide small area data similar to the long-form sample data published after Census
2000.
The Census Bureau is proposing to modify its current line of data products to accommodate
the 5-year estimates and is requesting comments from current and potential users of ACS
data products to help guide this modification.
We invite you to review the 5-Year ACS Data Release Plan and provide your response to the
contact listed in the Federal Register notice. Please follow this link to the Federal
Register notice (PDF files) posted in the Highlights section on the ACS Main page:
http://www.census.gov/acs/www/
Comments are due to the contact listed in the Federal Register notice by April 20, 2009
From the Census Bureau’s pdf document:
2. Detailed tables with more than 100 cells cannot be released at the block group level.
5. For the Selected Population Profiles, there must be at least 50 unweighted sample
cases
over the 5-year period in the universe (specific population subgroup) in a given
geographic area for the profile to be released.
6. For workplace tables, there must be at least 50 unweighted or 300 weighted workers in
sample over the 5-year period in a given workplace for the table to be released.
7. For the residence and workplace tables where means of transportation (mode) is
crossed
with one or more other variables, there must be at least three unweighted workers in
sample for each transportation mode in a given place for the table to be released.
Otherwise the data must be collapsed or suppressed and complementary suppression must
be applied. There is no threshold on univariate tables.
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Ed Christopher
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