TO: CTPP-News
Summary File #3 ("Long Form" or "Sample" data) has been released for five U.S. states: Delaware, New York, New Jersey, Vermont and West Virginia.
SF3 data for seven more states are planned for release on 8/13/02: Alabama, Colorado, District of Columbia, Maryland, Nebraska, Rhode Island and Utah.
SF3 data for an additional seven states are planned for release on 8/20/02: Connecticut, Illinois, Kentucky, Nevada, North Dakota, Oklahoma and Oregon.
The following "Press Release" link will be updated by the Bureau over the next month to provide expected release dates for the remaining states.
http://www.census.gov/Press-Release/www/2002/sumfile3.html
Chuck Purvis, MTC
TO: CTPP-News
FR: Chuck Purvis
I've taken the liberty and snipped a set of state data center listserv discussions related to the census Demographic Profiles. These e-mail discussions are from the past week, with most recent discussions first.
Basically, the weighted and expanded "long form" profile data show discrepancies with the "short form" profile/PL94-171/SF-1 datasets, especially for VERY small places less than 2,500 population.
NOTE that for the upcoming CTPP tabulations the minimum PLACE-LEVEL population threshhold is 2,500 persons....(Correct me if I'm wrong.)
Cheers, Chuck Purvis, MTC
****************************************************************************************
Your point about the 2,500 person cutoff for places in 1990 is a good one.
Those of us with many small towns noticed similar differences in 1990. For
example, when I looked at Nebraska towns with less than 2,500 persons in
1990, the mean absolute percent error comparing STF3 to STF1 was 5.7%. In
2000, for towns less than 2,500, it was 6.7 %. However if I threw out 2 towns with populations of 10 and 11, the MAPE becomes comparable at 5.9%.
The mean absolute deviation for 1990 was about 10 persons, and for 2000 it
was about 12 persons.
Based on this quick and dirty analysis, it looks like the estimation
problem may have worsened somewhat between 1990 and 2000, but it is not new to the 2000 census.
Jerry Deichert
Center for Public Affairs Research
University of Nebraska at Omaha
6001 Dodge Street
Omaha, NE 68182
****************************************************************************************
I wonder if this a result of the Bureau's use of Counties as the primary
sampling unit to determine the weights for population and housing counts on
the sample data. In 1990, they used areas (counties, MCDs, places, and
census tracts) over a relatively small population threshold (I think 2,500).
Leonard M. Gaines, Ph.D.
Research Specialist
Empire State Development
e-mail: lgaines(a)empire.state.ny.us
Empire State Development & NY State Data Center Web Sites:
http://www.empire.state.ny.us
****************************************************************************************
In New Jersey, most discrepancies between SF1 and SF3 were found in CDPs. The differences between the 100% and sample population counts were as high as 38.1% in Diamond Beach CDP (218 vs. 135) and 31.4% in Vista Center CDP (541 vs. 711).
Other than the CDPs, only 7 (out of 566) municipalities had 5% or more
differences in population or housing unit counts. Pine Valley Borough had
the largest discrepancies (20% in population, 66.7% in housing units). All
except one are tiny municipalities with less than 600 residents.
Sen-Yuan Wu
New Jersey Department of Labor
*************************************************************************************
Ken Darga has also documented DP discrepancies in Michigan. The Bureau is now aware of these problems and looking into the cause.
Linda [Gage, California State Data Center]
***************************************************************************************
John -
Thank you for the work on this. I am going to forward to the FSCPE listserve as well. It is interesting in that even a smaller community down the road from which is even smaller looks numerically better. If anyone wants to see the article that came out on Searchlight and a lesson on dealing with the press check http://www.lvrj.com/lvrj_home/2002/Jul-29-Mon-2002/news/19282077.html
[from Jeff Hardcastle, University of Nevada, Reno]
*************************************************************************************
There appear to be some problems with this. We ran a test with our DP datasets, comparing the 100% and sample counts for all places. The summary report can be viewed at http://mcdc2.missouri.edu/pub/data/sf3prof/check_totpops.pdf . The biggest problem, in terms of pct difference in the counts, is definitely in the very small places. There are 593 places in the country where the difference was 25% or more and 566 of these were for places with 500 people or less.
The report also includes a listing of these 593 places, sorted by state and descending Pct Difference. The winner of the worst sample estimate award is Blacksville CDP, Ga. They had a 100% count of 4 people, but the sample estimate was 52.
John Blodgett
OSEDA - Office of Social & Economic Data Analysis
U. of Missouri Outreach and Extension
blodgettj(a)umsystem.edu
URL: http://oseda.missouri.edu/jgb/
*************************************************************************************
I am not sure if this has happened to states for the Demographic
Profiles that include SF1 and SF3 data but in Nevada's case there are
serious problems that suggest that the whole set of profiles needs to be
reviewed for errors. These errors appear to be more than standard
sampling and response errors. During a quick review counties look
better than places however it appears that there may be geocoding
errores in the sample data. There also appears to be differences in
what the sample data is weighted against.
The place that brought this to my attention was Searchlight NV where the
DP-1 pop is 576 and the housing unit count is 444. On DP-2 through 4
the pop is 768 and the unit count is 595. A 33% and a 34% difference
respectively. The way I tumbled to this was that a reporter had seen
that Searchlight had no native Nevadans living there. He went to
Searchlight and interviewed people and found that most of them if not
all were natives. (Searchlight is an old mining down south of Las Vegas
and in the middle of very open country.)
Is this kind of error being found elsewhere?
Jeff Hardcastle
(775) 784-6353 Phone
(775) 784-4337 Fax
jhardcas(a)unr.edu e-mail
"shifts happen" http://publicconversations.org/
*************************************************************************************
We're down to the last few days to accept materials for the proposed poster
session. I would like to encourage all to seriously consider this unique
opportunity to share your analytical methodologies and findings with others
who will be using released and soon to be released census products. SF3
will provide ample data for a wide range of analysis. Ideally, the analyses
would combine both tabular and spatial representation of the current data as
well as the ability to analyze the historical changes found from previous
census releases.
Please feel free to share your thoughts about the types of analysis you may
want to see, related to transportation planning, environmental justice,
etc.... Thanks for your support.
Previous transmittal.....
Attached is a "poster" session call for materials that the TRB subcommittee
on Census Data for Transportation Planning has issued. The subcommittee is
offering individuals the opportunity to show off the innovative and creative
ways they are presenting, analyzing and displaying their census data. If you
are doing something with your data that you want to show others this poster
session is for you. If you know others doing "innovative and creative" work
with their data please pass this along to them.
For lack of another electronic forum, the CTPP listserv has become a place for people to discuss MPO issues unrelated to Census data. However, we would like to keep the CTPP listserv focused on CTPP and Census data.
Alex Taft, the Executive Director of the Association of Metropolitan Planning Organizations (AMPO), has graciously offered to open up their listserv to non-members, since some non-members already belong. Information from AMPO follows:
" The list serve is also a vehicle for networking among AMPO members. If you are seeking advice from your peers or spreading information that will be useful to other MPOs, you can send a message directly to everyone on the list.
· If you wish to send your own message to subscribers of the list-serve, use the address: ampo(a)scpp.ubalt.edu. To send such a message, do not use the majordomo address that you used to subscribe to the list.
· If you are sending documents as part of your message to subscribers, it is preferable to cut-and-paste text directly into your e-mail; other subscribers may not have the appropriate program to download attachments.
· If you ever want to subscribe to this mailing list, send a request to majordomo(a)scpp.ubalt.edu and type the following command in the body of your message:
subscribe ampo
or from another account:
subscribe ampo <address name>
There is a confirmation step following this.
· If you want to know who has subscribed to the list, send a request to majordomo(a)scpp.ubalt.edu and type the following command in the body of your message:
who ampo
· If you ever want to remove yourself from this mailing list, send a request to majordomo(a)scpp.ubalt.edu and type the following command in the body of your message:
unsubscribe ampo
or from another account:
unsubscribe ampo <address name>
Please contact DeLania Hardy at dhardy(a)ampo.org with any questions. And again, welcome to the AMPO list-serve."
i just pulled this off a census bureau press release. looks like the
SF3s will be starting to roll.
========
Earlier this month, the Census Bureau delayed the release of the Summary
File 3 (SF3) for the state of Vermont after identifying a potential
problem
with the data. In accordance with our long-standing commitment to
quality,
we have revised the schedule for releasing the SF3 files for Vermont,
Delaware, New York, New Jersey and West Virginia and will now release
these
state files for embargoed access on Wednesday, July 31, 2002, for public
release on Tuesday, August 6, 2002.
If you have an interest in the development and dissemination of Transit Cooperative Research Project (TCRP) problem statements and reports
you may wish to take their online survey at:
http://www.tcrponline.org/
The survey invitation should pop up when you go to the site. If you are not interested in this just delete this message.
Peter J. Foote
PFoote(a)TransitChicago.com
Market Research/Resource Planning
Planning Division
Chicago Transit Authority
120 N. Racine Avenue
Chicago, IL 60607
(312) 733-7000 x 6840 (Voice)
(312) 432 - 7108 (Fax)
****************************************************************************
****************************************************************************
*******************************************
Unless otherwise stated, the views expressed are those of the author and not
those of the Chicago Transit Authority.
****************************************************************************
****************************************************************************
*******************************************
http://www.TransitChicago.com
CTA CUSTOMER SERVICE HOTLINE
1-888-YOUR-CTA
RTA Travel Information
836-7000
The message is confusing because they have confused two separate products.
There is both a county-to-county migration dataset and a county-to-county
commuting dataset. Both are projected to be released by the end of the
year (December '02). The commuting file will be very similar to the 1990
STF-S5 product that is now up on the census web site. (From the census home
page, www.census.gov, click on "J" in the Subjects A to Z index, then on
the link to "Journey to work and Place of Work Data," and then on the link
to "1990 County-to-County Worker Flow Files," or go directly to
http://www.census.gov/population/www/socdemo/jtw_workerflow.html. The
migration file will be quite different from previous censuses, consisting
of a suite of smaller, more manageable files than we have produced in the
past.
--Phil
"Chuck Purvis"
<CPurvis(a)mtc.ca.g To: <ctpp-news(a)chrispy.net>
ov> cc:
Sent by: Subject: [CTPP] Forwarded Message: Update of
owner-ctpp-news@c State Data Center meeting with Census
hrispy.net
07/19/2002 11:35
AM
TO: CTPP-News
This is a message from the State Data Center (SDC) steering committee
regarding a recent meeting with the Census Liaision Office (CLO).
What is notable is the delay in the release of SF3, as well as discussions
about the Census Transportation Planning Package (CTPP) between the State
Data Centers and the Census Bureau. This is encouraging, that is, the
interest of the State Data Center folks in the CTPP.
Another point is that the Census Bureau will purportedly provide:
"County to County migration (Journey to Work), Dec '02" (The word
"Migration" is confusing. What I think is meant is that the
county-to-county total workers commuting matrix, not by means of
transportation, will be released in December 2002. This is similar - - I
hope - - to the same type of file that was released December 1992. Can
J-T-W Branch clarify this particular product?)
Chuck Purvis, MTC
**** Message from SDC listserv *******************************************
The SDC/BIDC steering committee met with CLO and other Bureau staff last
week. This is the first of several brief updates on products, program
updates and items of concern:
High priority products in the pipeline:
SF3 is under intense scrutiny. The Census Bureau is attempting to make
sure that the files are accurate before releasing. Instead of releasing VT
alone several states are being reviewed and may be released together.
A Voting District File has also been given top priority and is scheduled
for release in early Aug. via federal register. Congress amended the Voting
Rights Act of 1965, Title 42, United States Code, 1973 et seq. (See Public
Law102-344.) Among other changes, the minority language assistance
provision set forth in Section 203 of the Act was extended to August 6,
2007. The geography will be states and counties or county equivalents (MCD
states) and American Indian Areas (ANVSA's etc.).
Other products of interest with tentative release dates:
LandView V August '02 (first counties avail)
MARS August '02
EEO, June-July '03
Census Transportation Planning Package, The Census Bureau will deliver the
residence based file to the Amer. Assn. of State Hghwy & Transportation
Officials and DOT ) Oct-Dec '02; Census will deliver the work place and
commuter flow state files to ASHTO and DOT beginning in Apr '03. ASHTO and
DOT will will decide on public release dates.
County to County migration (Journey to Work), Dec '02
Other items of interest:
The Summary File 2 PCT 5 Household Population by sex by age (for race and
Hispanic/Latino) table will be regeneraterated for each person in the
household (to be comparable with 1990 SF2). This will be done after the
Census Bureau completes the processing of the Summary File 3 data. Renee
Jefferson-Copeland will send an inquiry to the leads to determine the level
of GEO each state needs and, if the SDC uses this table to produce state
level population estimates and projections, the date they would need the
new table.
Abnormalities in the DP3 unemployment for areas with high concentrations of
group quarters are being investigated, but may take a while to determine
the true cause.
TIGER/Master Address File update to realign to true coordinates; contract
awarded with expectation of completing all counties by '07
Please contact me or any other steering committee member if you have any
questions. Jane
Jane Traynham
Maryland Department of Planning
MD State Data Center
301 West Preston St.
Baltimore, MD 21201
******** end of message from SDC listserv
************************************
***********************************************
Charles L. Purvis, AICP
Senior Transportation Planner/Analyst
Metropolitan Transportation Commission
101 Eighth Street
Oakland, CA 94607-4700
(510) 464-7731 (office)
(510) 464-7848 (fax)
www: http://www.mtc.ca.gov/
Census WWW: http://census.mtc.ca.gov/
***********************************************
TO: CTPP-News
This is a message from the State Data Center (SDC) steering committee regarding a recent meeting with the Census Liaision Office (CLO).
What is notable is the delay in the release of SF3, as well as discussions about the Census Transportation Planning Package (CTPP) between the State Data Centers and the Census Bureau. This is encouraging, that is, the interest of the State Data Center folks in the CTPP.
Another point is that the Census Bureau will purportedly provide:
"County to County migration (Journey to Work), Dec '02" (The word "Migration" is confusing. What I think is meant is that the county-to-county total workers commuting matrix, not by means of transportation, will be released in December 2002. This is similar - - I hope - - to the same type of file that was released December 1992. Can J-T-W Branch clarify this particular product?)
Chuck Purvis, MTC
**** Message from SDC listserv *******************************************
The SDC/BIDC steering committee met with CLO and other Bureau staff last week. This is the first of several brief updates on products, program updates and items of concern:
High priority products in the pipeline:
SF3 is under intense scrutiny. The Census Bureau is attempting to make sure that the files are accurate before releasing. Instead of releasing VT alone several states are being reviewed and may be released together.
A Voting District File has also been given top priority and is scheduled for release in early Aug. via federal register. Congress amended the Voting Rights Act of 1965, Title 42, United States Code, 1973 et seq. (See Public Law102-344.) Among other changes, the minority language assistance provision set forth in Section 203 of the Act was extended to August 6, 2007. The geography will be states and counties or county equivalents (MCD states) and American Indian Areas (ANVSA's etc.).
Other products of interest with tentative release dates:
LandView V August '02 (first counties avail)
MARS August '02
EEO, June-July '03
Census Transportation Planning Package, The Census Bureau will deliver the residence based file to the Amer. Assn. of State Hghwy & Transportation Officials and DOT ) Oct-Dec '02; Census will deliver the work place and commuter flow state files to ASHTO and DOT beginning in Apr '03. ASHTO and DOT will will decide on public release dates.
County to County migration (Journey to Work), Dec '02
Other items of interest:
The Summary File 2 PCT 5 Household Population by sex by age (for race and Hispanic/Latino) table will be regeneraterated for each person in the
household (to be comparable with 1990 SF2). This will be done after the Census Bureau completes the processing of the Summary File 3 data. Renee Jefferson-Copeland will send an inquiry to the leads to determine the level of GEO each state needs and, if the SDC uses this table to produce state level population estimates and projections, the date they would need the new table.
Abnormalities in the DP3 unemployment for areas with high concentrations of group quarters are being investigated, but may take a while to determine the true cause.
TIGER/Master Address File update to realign to true coordinates; contract awarded with expectation of completing all counties by '07
Please contact me or any other steering committee member if you have any questions. Jane
Jane Traynham
Maryland Department of Planning
MD State Data Center
301 West Preston St.
Baltimore, MD 21201
******** end of message from SDC listserv ************************************
***********************************************
Charles L. Purvis, AICP
Senior Transportation Planner/Analyst
Metropolitan Transportation Commission
101 Eighth Street
Oakland, CA 94607-4700
(510) 464-7731 (office)
(510) 464-7848 (fax)
www: http://www.mtc.ca.gov/
Census WWW: http://census.mtc.ca.gov/
***********************************************
Here is a colleague of mine challenging the validity of the 2000
Census data on transit ridership. I am not a statistician and have no
way of assessing the soundness of his claims. Can anybody help me?
Ken Orski
-------- Original Message --------
Subject: Re: "The Truth About Transit", Baltimore Sun, July 12, 2002
Date: Fri, 12 Jul 2002 15:48:00 -0400
From:"Tom Downs" <tdowns(a)ursp.umd.edu>
To: <korski(a)erols.com>
C Kenneth Orski wrote:
>
> You should read this... and ponder
>
http://www.baltimoresun.com/news/opinion/oped/bal-op.transit12jul12.story?c…
=======================
I would be glad to ponder the following:The survey data, census long
form, is increasingly viewed as biased in its results (response rates of
less than 20% in many regions, language biased in an age of immigrants,
poverty biased, and generally reflective of a white middle class data
set)The data does not reflect the fact that journey to work is about 20%
of trips and declining. Do we care about the explosion in "other trips"
and transit's role in them? We also have no clue as to what is happening
to pedestrian trips...Tom Downs
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