One correction: My e-mail address is Nanda.Srinivasan(a)fhwa.dot.gov
Thank you
Nanda Srinivasan
202-366-5021
-----Original Message-----
From: clara.a.reschovsky(a)census.gov
[mailto:clara.a.reschovsky@census.gov]
Sent: Tuesday, March 23, 2004 3:31 PM
To: ctpp-news(a)chrispy.net
Subject: [CTPP] CTPP Part 2 Comments due March 31
MPO and State DOT users:
By now you should have had a chance to review the data from the Part 2 CDs.
Any comments you have should be communicated to Nanda Srinivasan at either
202-366-5021 or Nandu.Srinivasan(a)fhwa.dot.gov by next Wednesday, March 31.
Thanks for your time in looking at the data.
We are about to start sending out Part 1 Final data and will make the Part
3 ASCII data available soon as well. If you have any questions about the
timing of the other parts, contact Phil Salopek or me at 301-763-2454 or
Phillip.A.Salopek(a)census.gov or Clara.A.Reschovsky(a)census.gov.
Clara Reschovsky
_______________________________________________
ctpp-news mailing list
ctpp-news(a)chrispy.net
http://www.chrispy.net/mailman/listinfo/ctpp-news
MPO and State DOT users:
By now you should have had a chance to review the data from the Part 2 CDs.
Any comments you have should be communicated to Nanda Srinivasan at either
202-366-5021 or Nandu.Srinivasan(a)fhwa.dot.gov by next Wednesday, March 31.
Thanks for your time in looking at the data.
We are about to start sending out Part 1 Final data and will make the Part
3 ASCII data available soon as well. If you have any questions about the
timing of the other parts, contact Phil Salopek or me at 301-763-2454 or
Phillip.A.Salopek(a)census.gov or Clara.A.Reschovsky(a)census.gov.
Clara Reschovsky
TO: CTPP-News
Last week the Census Bureau released a 13-page "Census Brief" on
"Journey to Work: 2000". The report, authored by Clara Reschovsky of the
Census Bureau, is #C2KBR-33, the 33rd in a series of short, general
interest census reports. It is available at:
http://www.census.gov/prod/2004pubs/c2kbr-33.pdf
or, for the site listing all of the census briefs and special reports:
http://www.census.gov/population/www/cen2000/briefs.html
There's an interesting table (Table 6) ranking the top 10 metro areas
by different means of transportation shares.
This is a good report to provide to your executive director and
management, to provide the "big picture" on commuting in America. Just
be sure to use a color printer due to the full-color U.S. maps included
in these briefs. Very helpful report.
Chuck Purvis, MTC
*************************************************************************************************************************************
IMMEDIATE RELEASE
MONDAY, MARCH 15, 2004
Mike Bergman
CB04-42
Public Information Office
(301) 763-3030/457-3670 (fax)
(301) 457-1037 (TDD)
e-mail: <pio(a)census.gov>
More on 'The Daily Grind'
Commute to Work: It's Early, Lonely and Long,
Census Bureau Confirms
The typical U.S. commuter in 2000 left home between 6:30 a.m.
and
8:29 a.m. and drove alone for 26 minutes to get to work, the U.S.
Census
Bureau said today in a report based on Census 2000 results. Overall,
people
were leaving home earlier and spending more time in traffic in 2000
than in
previous censuses.
According to the report, Journey to Work: 2000, about 53 percent
of
all workers headed to their jobs between 6:30 a.m. and 8:29 a.m.
Another 20
percent of workers departed for work between midnight and 6:29 a.m, up
2
percentage points or 4.8 million workers from a decade earlier, the
largest
hike in any time period of the day.
The report is based on responses to questions asked on the
census
long form, which did not include the distance workers traveled in
their
journey to work. A sample of households, about 1-in-6 nationally,
received the long form. The data are subject to sampling and
nonsampling
error.
-X-
Editor's Note: The report can be accessed at
<http://www.census.gov/pop/www/cen2000/briefs.html>.
Attached is a call for abstracts for a conference on the National
Household Travel Survey sponsored by the Transportation Research Board
this coming November. The NHTS complements the CTPP. for more
information on the conference please visit
http://trb.org/calendar/event.asp?id=125
--
Ed Christopher
708-283-3534 (V) 708-574-8131 (cell)
708-283-3501 (F)
On behalf of everyone on the listserv, we owe Chuck Purvis a big thanks
for his guidance and assistance on everything Census- and
transportation-related.
TO: CTPP-News
The State Data Center network has posted some very useful information,
provided by Census Bureau staff, in the comparison of employed resident
data from the decennial census and the CPS (Current Population Survey).
These notes were provided to the SDC network as part of a recent SDC
committee meeting, and they are available at:
http://www.sdcbidc.iupui.edu/html/news_.html
go to the link: "Notes from Tom Palumbo of HHES" to download a WORD
document.
One site mentioned in Mr. Palumbo's notes is worth mentioning: the
Census Bureau page, here:
http://www.census.gov/hhes/www/laborfor.html
on "labor force statistics."
What may be very useful (to some) is the 92-page report: "Comparing
Employment, Income, and Poverty: Census 2000 and Current Population
Survey"
Hope this is helpful.
Chuck Purvis, MTC
**************************************************************
Charles L. Purvis, AICP
Principal 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://www.bayareacensus.ca.gov/
**************************************************************
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Long post from Elaine Murakami, Federal Highway Administration
ACS 2000-2002 Change profiles
WARNING: It is not appropriate to compare decennial Census 2000 numbers directly with the ACS 2002 results.
We agree (with Phil Salopek) that it is not wise to compare the "current" ACS results directly with decennial 2000, since it appears that methodological differences are making a significant difference in variables like travel time.
It is BETTER to compare ACS 2000 figures with ACS 2002 to determine if there has been significant change.
The Census Bureau issued a press release on Feb 25, 2004 related to data from the American Community Survey. Right now, the ACS is not in "full implementation" (expected to begin in July 2004). However, an annual sample (1203 counties of 3141 counties in the U.S. are included) is surveyed over 12 months and the results are available for large geographic units (states and some counties). http://www.census.gov/acs/www/Products/Tables/Tables1.htm Under full implementation, all counties will be surveyed.
To access the 2000-2002 Change Profiles available for States and large Metropolitan Areas, go to http://www.census.gov/acs/www/Products/Profiles/Chg/2002/0002/index.htm
Once you have selected a geography, select the 3rd page of the profile to find tables on means of transportation to work and average commute time. We have extracted State level geography for average travel time, number of workers and percent of workers using transit for their usual commute and it is attached as a spreadsheet.
Recently, on the CTPP and the State Data Center listservs there have been discussions about the differences between the two surveys, particularly when people use decennial 2000 data, and then ACS 2002 data, without understanding that the ACS 2000 number may differ significantly. For example:
% Carpool to work, US Total
2000 decennial 12.2%
2000 ACS 11.2%
2002 ACS 10.4%
It would be misleading to say that carpooling declines by 1.8% between 2000 and 2002. It is probably better to say that carpooling declined by .5% (after assumptions about errors are incorporated).
Similar differences occur when comparing average commute times.
Average Travel Time to Work, US Total
2000 decennial 25.5 minutes
2000 ACS 24.4 minutes
2002 ACS 24.4 minutes
It would be misleading to say that average travel times have declined by 1 minute, when it is more accurate to say that the average travel time remained the same.
So far, we believe that the key factors that contribute to the difference between decennial and ACS results include:
a. Seasonality (12 months instead of "April 1") (different jobs and workers, especially in summer)
b. ACS does not currently include group quarters population.
c. ACS has only one-third of counties of the country represented.
d. Differences in Non-response follow-up
e. Data collection period (ACS is very long, compared to very short in decennial)
FHWA research conducted by Westat, using 1999-2001 ACS data, showed that average travel times were significantly different between the ACS and the decennial. Generally speaking, average travel times in Census 2000 are from .8 min to 1.8 minutes LONGER than the ACS reported times.
Pima County ACS 25.2 Decennial 26.7 *
San Francisco 33.3 34.6 *
Broward, FL 28.7 30.5 *
Lake, IL 34.6 34.0 *
Flathead, MT 20.6 21.4
Bronx, NY 48.0 49.2 *
* = significantly diff
When examined spatially (by tract) and by mode, there was no pattern found in our limited research to explain the difference. We did not compare by month or season, but some of us suspect some seasonality differences. Another factor may be that the decennial is more likely to capture longer distance commutes. We have not yet been able to compare this, but I hope the NCHRP project on the ACS for transportation planning will explore this issue.
Other researchers believe that the use of better-trained, experienced field interviewers is resulting in overall higher quality data in the ACS.
Reporting at small geographic units
Because the ACS surveys a small sample continuously, for reporting at small geographic units (smaller than 250,000 population), samples over multiple years will averaged. (Note from Elaine—we really don’t know what this means, but are working with the CB to get a better handle on it). For counties or places (e.g. incorporated cities) with population between 65,000 and 250,000, a three-year average can be reported. For areas with less than 65,000, it will require a five-year average before reporting.
Last words (at least for today)
There are many questions about ACS yet to be answered. The Census Bureau plans to release a series of reports comparing the 1999-2001 ACS test to the decennial census 2000 this Spring. Fiscal year 2005 will be first year when the Census Bureau requests a budget to cover a full 12-months of data collection costs for the ACS. The ACS will require 5 years of data collection before small area reporting can occur. The Census Bureau has promised the transportation community that "small area reporting" includes Block Group and TAZ reporting. However, any cuts to sample size would seriously impact this ability for small area tabultion.
The email shown reproduce below was posted by Thabet Zakaria. Because
of the volume of spam/viruses in the last few weeks it inadvertently got
snagged by our filtering system. I have reposted it below along with
its original attachment..
MEMORANDUM
Date: February 27, 2004
To: ctpp_news(a)chrispy.net
From: Thabet Zakaria, Ph.D.
Subject: Interesting Results from the ACS
The recent e-mails to the cttp network are interesting. Dr. Edward L.
Hillsman and his colleague have found out that the average 2002 commute
time to work from the ACS for King County, WA was 5.7% lower than that
obtained from the 2000 census. They also indicated that the average
commute time over the two year period is down 10% in Washington, DC. Ed
Christopher of the FHWA tells us that the Census Bureau is going to have
a news conference to discuss new ACS data which show that Albany County
residents have higher levels of education and household income than the
average resident of New York state. These conclusions are based on the
results of the ACS that was conducted nation-wide in the last several
years based on a small sample of households.
Last year, I reviewed the ACS estimates for the basic variables needed
for transportation planning in the DVRPC region, which includes five
counties in Pennsylvania and four in New Jersey and found the following:
1. The errors in the county estimates of population and employment are
very large and cannot be compared to the Year 2000 census (about 6%).
For example, the ACS underestimated the population of the City of
Philadelphia, PA by 54,731 people.
2. The errors in the means of transportation to work estimates are even
larger than those for population and employment (about 25%). For
example, the standard error in the estimates of means of transportation
for Mercer County, NJ ranges from 4.54 to 30.69% for workers who drove
alone or took buses to commute to work, respectively.
These erroneous findings are expected since the sample size is too small
to produce comparable estimates to the Year 2000 census. Based on these
results, we concluded that ACS estimates cannot be used for any of
DVRPCs transportation planning studies. The ACS estimates cannot be
compared to the decennial census because the sampling errors in the ACS
results are much higher. In summary, the current ACS results cannot be
used to make rational conclusions for transportation planning analysis.
TZ:ms
