TO: CTPP-News, August 13, 2002
Summary File #3 (Long Form, Sample data) has been released for an additional six states plus the District of Columbia: Alabama, Colorado, District of Columbia, Maryland, Nebraska, Rhode Island and Utah.
Data released in the previous week include: Delaware, New York, New Jersey, Vermont and West Virginia.
SF3 data for an additional seven states are planned for release on 8/20/02: Connecticut, Illinois, Kentucky, Nevada, North Dakota, Oklahoma and Oregon.
And, new information for tody: SF3 data will be released for seven states on 8/27/02: Iowa, Kansas, Massachusetts, Missouri, Montana, New Mexico and Ohio.
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
BE SURE TO DOWNLOAD THE SF3 DOCUMENTATION FROM THE ABOVE LINK.
For "power users" interested in SPSS and SAS code to work with these databases, visit the State Data Centers web site at:
http://www.sdcbidc.iupui.edu/Profiles/SF3/sf3.html
The 77 files that comprise each state's set of SF3 files is fairly intimidating, so I would recommend becoming friendly with American FactFinder when your state's data becomes available.
American Factfinder: http://factfinder.census.gov/
Chuck Purvis, MTC
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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/
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The Census Bureau posts 1980, 1990, and 2000 data at http://www2.census.gov/. I found technical documentation for 1990 and 2000, but I was not able to find any documentation for 1980 data. Thus, I have not been able to incorporate the 1980 data yet. Does anyone know where I could find technical documentation for the 1980 data? Thanks, Daryl
--
Daryl Scott
South Western Regional Planning Agency
Stamford Government Center
888 Washington Blvd., 3rd Floor
Stamford, CT 06901
Tel: (203) 316-5190
Fax: (203) 316-4995
E-mail: dscott(a)swrpa.org
-----Original Message-----
From: Adam Garms [mailto:ajgarms@dmampo.org]
Sent: Friday, August 09, 2002 3:56 PM
To: ctpp-news(a)chrispy.net
Subject: [CTPP] Historical Census Data
We have been looking for historical census data and have had a difficult time. The data we are specifically looking for is population and housing information at the block level for 1990. But we would also like to find data from 1980 if possible. We are trying to look at some of the trends in our area that have changed over time. Part of the study area for one of the projects is in a rural area and data at block group and track levels are very broad and difficult to determine trends. If anyone has any suggestions on where we could find this data it would be greatly appreciated. Thank you in advance for your help.
Thanks,
Adam J Garms
Transportation Planner
Des Moines Area Metropolitan Planning Organization
Merle Hay Centre
6200 Aurora Avenue, Suite 300W
Urbandale, IA 50322-2866
Telephone: 515.334.0075 ext. 202
Facsimile: 515.334.0098
AJGarms(a)dmampo.org
The travel behavior inventory conducted in the Denver region (1997) obtained
a count on the number of (paid and volunteer) jobs a person had. The data
implied about 7.5% of the employed household population had 2 or more jobs.
Some reported as many as 4 other jobs. While clerical employees were the
largest group with second jobs, none reported more than 1 additional job.
Those employed as "professionals" accounted for 46% of the employed with 2
or more other jobs (3+ totals jobs).
-----Original Message-----
From: David Abrams [mailto:dabrams@mrgcog.org]
Sent: July 08, 2002 4:28 PM
To: 'Chuck Purvis'; ctpp-news(a)chrispy.net
Subject: RE: [CTPP] Changes in Workers per HH and Vehicles per HH
(long po st)
Albuquerque (not one of your 36 largest MSAs) also had a decline in workers
per household from 1.235 to 1.188. We looked at the employment number
compared to the employment data coming from the Department of Labor. We
found that the number of workers (326,775) was somewhat less than the NMDOL
estimate of Nonagricultural Employment (354,883). The NonAg number does not
count agricultural or self-employment both of which are included in the
number of workers (employed residents). In 1990, the number of workers
reported by the Census exceeded the estimate of NonAg employment. We are
thinking that there may be a major increase in persons working two jobs. If
this is more widespread than Albuquerque it could have considerable
consequences. To my knowledge there is not data collected on workers
working multiple wage jobs.
A question for Chuck Purvis: Did you control for the change in household
size when you compared the workers to households ratios for 1990 and 2000.
Dave Abrams
Middle Rio Grande Council of Governments
We have been looking for historical census data and have had a difficult time. The data we are specifically looking for is population and housing information at the block level for 1990. But we would also like to find data from 1980 if possible. We are trying to look at some of the trends in our area that have changed over time. Part of the study area for one of the projects is in a rural area and data at block group and track levels are very broad and difficult to determine trends. If anyone has any suggestions on where we could find this data it would be greatly appreciated. Thank you in advance for your help.
Thanks,
Adam J Garms
Transportation Planner
Des Moines Area Metropolitan Planning Organization
Merle Hay Centre
6200 Aurora Avenue, Suite 300W
Urbandale, IA 50322-2866
Telephone: 515.334.0075 ext. 202
Facsimile: 515.334.0098
AJGarms(a)dmampo.org
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
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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
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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
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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
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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]
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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]
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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/
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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/
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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.
