8 Jun
2007
8 Jun
'07
noon
Marie--I think you might be confusing some folks in the transportation
world when your talk about MIGPUMA and POWPUMA. We really do not look
at the world quite that way. You are absolutely right in what you say
about what the CB produces as part of their standard products which is
one of the reasons the transportation community has gone off and
purchased its own set of special tabulations.
One of the issues that frustrated the transportation with the 2000 data
was that you could not get data that was a standard product that had
PUMA of Work coded on the pums record. You could only get county of
work. That meant your flow would be PUMA to county of work. The
transportation community has asked all along for to see the PUMS data
coded to PUMA of work but the CB for whatever reason doesn't code all
the records down to that area of geography.
For our CTPP tabulation we had developed a process to extend the
geocoding down to the smallest areas (block faces or what ever they are
called today) for all the records that could not get coded. We called it
extended allocation and Elaine has early research work going on to help
get it incorporated into the standard process schema at the CB. The
extended allocation process was what was used for all the CTPP data
which is why we have the flows that we do at so many geographies and
with such high quality.
While the CB might not have the product you need unless you are LA, the
CTPP will produce what you are after for 2000, 1990 and even 1980 in the
Chicago region. CTPP did have place as summary geography. CTPP does
not have PUMA a summary geography for 2000 but in the future it will.
I am not sure if I helped clarify or only confused the matters. One of
the things that makes all of this even more confusing is that we all use
slightly different terms. I never thought of the data in terms of MIG
and POW PUMAs.
Marie--good to hear from you. What always drove me crazy we those few
residents who lived in Chicago but were actually were in Dupage County.
It was up around O'Hare and in 1990 kept causing my tables not to
balance, until I finally figured out. For 2000 in CTPP you do not have
to worry about all the tables balancing due the rounding and threshold
requirements on the data which is a whole other story....
mbousfield(a)cityofchicago.org wrote:
To CTPP-News Maillist and Other Census Groupies,
Much thanks to all who shared their migpuma concerns.
The attached file defines the migpumas and the powpumas in function of
the pumas (all 5%). I downloaded it from Blodgettâs Mable database.
For instance, for Illinois (17), the pumas 3501-3519 cover the City of
Chicago and pumas 3401-3414 cover the remainder of Cook County which we
call suburban Cook County. The file shows that powpuma 3500 coincides
with the city of Chicago and that migpuma 3490 coincides with Cook
County.
We at the City defined the pumas but the definitions of the powpumas
and migpumas were done by the CB. In 1990, Chicago was a migpuma but
in 2000 the CB decided it was no longer. According to Clara, no county
remainders were migpumas except Los Angeles city, why not Chicago city?
I planned to extract the population sizes off all the migpumas and show
that there are many migpumas that are smaller than the City of Chicago
thereby showing a lack of equal access to data. According to
âPrinciples and Practices for Federal Statistical Agenciesâ by
Martin, Straf, and Citro, federal statistical agencies have to ensure
equal access to data. Are large subcounty cities with concentrations of
minority persons getting equal access to data?
Thank you,
Marie Bousfield, Demographer
City of Chicago
Department of Planning and Development
City Hall, Room 1003
121 North LaSalle Street
Chicago, Illinois 60602
Tel. (312) 744-6536
Fax. (312) 744-0759
Email mbousfield(a)cityofchicago.org
http://www.cityofchicago.org
--
Ed Christopher
708-283-3534 (V)
708-574-8131 (cell)
FHWA RC-TST-PLN
19900 Governors Dr
Olympia Fields, IL 60461
>> "Murakami, Elaine"
<Elaine.Murakami(a)fhwa.dot.gov> 6/6/2007 5:19 PM
>>
Hello Marie --
Well, you learn something new everyday. I have never heard of a
migpuma
before!
I agree with you that PUMA geography and the PUMS are not just for
academic research. We are happy that the CB now includes residence
PUMA
as a tabulation geography as part of the 2005 ACS standard
tabulations.
This benefits large cities, like Chicago. Maybe Table B07204 or
C07204
"residence 1 year ago: State/County/place level" would be useful to
you?
Right now, in the ACS PUMS dataset, POW-PUMA is not a "real" PUMA. It
is
generally limited to County, as the "basic" workplace coding completed
at the CB is to County-Place. In order to have a "real" POW-PUMA, the
Census Bureau will need to complete extended workplace allocation
(imputation) process for responses with ungeocoded workplace
addresses.
This is because to assign workers to a "real" PUMA, the coding needs
to
be complete to the census block level. Ungeocoded records continue to
be between 20-25 % of workers, similar to the Census 2000. I hope
that
the extended workplace allocation will be established and part of the
NEXT CTPP, so that we can have PUMA-to-PUMA flows where the POW-PUMA
is
not a county.
There has been some informal discussion among the CTPP Technical
Working
Group about whether a "special" ACS PUMS file with the POW-PUMAs after
extended allocation has been completed would be possible, as part of
CTPP. We would have to take this to the CB's Disclosure Review Board
(as ALL tabulation and products go through the same review) for their
consideration.
This link is the ACS list of the POW-PUMAs. For example, 04890
includes
nearly 100 places and the "remainder" of Los Angeles County; 08100
includes 47 places and the remainder of San Diego County. I don't
know
how many "real" PUMAs there are in Los Angeles County, but it is
probably nearly 100. I didn't look at Chicago, but I'm sure it has a
similar scale of loss of geographic detail.
http://www.census.gov/acs/www/Products/PUMS/C2SS/CodeList/2005/POWPUMA20
05lookup.htm
here is the list for the ACS MIG-PUMAs.
http://www.census.gov/acs/www/Products/PUMS/C2SS/CodeList/2005/MIGPUMA20
05lookup.htm
We understand that the Census Bureau staff are generally not allowed
to
post messages to listservs, but I'm sure they will read your message
and
consider your ideas for ACS PUMS files.
Elaine Murakami
FHWA Office of Planning
-----Original Message-----
From: ctpp-news-bounces(a)chrispy.net
[mailto:ctpp-news-bounces@chrispy.net] On Behalf Of
mbousfield(a)cityofchicago.org
Sent: Wednesday, June 06, 2007 1:34 PM
To: Ed Christopher
Cc: ctpp-news maillist
Subject: Re: [CTPP] Brainstorming about INCOME variable for the
futureCTPP(using ACS records)
To CTPP-News Maillist and Other Census Groupies,
Comments about Elaine Murakami's email and Ed Christopher's email
both dated 5/31/07 with subject: [Brainstorming] about income
variable....
Elaine lists four presumed-wanted flows: county to county, place to
place, county to place, and place to county. These are insufficient
for
many subregional analyses when the principal city is part of one or
more
counties. In these cases, we need city to county remainder data and
county remainder to city data.
In 1980 and 1990, the City of Chicago was a migpuma This allowed us
to do city to county remainder and county remainder to city analyses.
For instance, using the PUMS file we analyzed inmigration and
outmigration by characteristic between the City of Chicago and its
suburbs.
In 2000, the City of Chicago was not a migpuma even though many
smaller
areas were migpumas. The Census Bureau person Ms. Showalter told me
that
no city of any size was a migpuma unless it coincided with one or more
counties such as the City of New York. As a consequence, we were not
able to determine in and outmigration between the City of Chicago and
the suburbs for the 1995-2000 period.
In the future ACS-PUMS are large cities like the City of Chicago
identified as migpumas and powpumas? I noticed that the 2004 ACS PUMS
has only MIGSTATE (allowing to determine the state of origin of
movers.)
Can we please restore large cities as migpumas and powpumas and
identify the pumas, migpumas, and powpumas on the ACS-PUMS.
On their website, the Census Bureau claims that the ACS-PUMS file is
used for academic research. But my experience as a city demographer
shows that the PUMS files are very important tools in city management.
Please help if you are in a position to do so. Thank you,
Marie Bousfield, Demographer
City of Chicago
Department of Planning and Development
City Hall, Room 703
121 North LaSalle Street
Chicago, Illinois 60602
Tel. (312) 744-6536
Fax. (312) 744-0759
Email mbousfield(a)cityofchicago.org
http://www.cityofchicago.org
_______________________________________________
ctpp-news mailing list
ctpp-news(a)chrispy.net
http://www.chrispy.net/mailman/listinfo/ctpp-news
------------------------------------------------------------------------
Name: puma5_xtract.xls
puma5_xtract.xls Type: Microsoft Excel Worksheet (application/vnd.ms-excel)
Encoding: base64