2 Feb
2011
2 Feb
'11
8:46 a.m.
Hi Frank--
Hope the new year is treating you well.
You asked what you're missing: How is the 3-year or 5-year window *not* like a moving
average?
Some of the moving parts changing from year to year are the control totals and, as result,
the weights (expansion factor) that would be attached to any given household found in the
5 annual sub-samples that comprise the period sample.
The population control totals come an exogenous, completely-outside-the-survey-itself,
annual estimation model. And in our region, Mpls-St Paul, CB badly underestimated the
top-line population totals during early and mid-decade. I think they realized it (oops),
and they've been trying to make up ground ever since.
Also pertaining to control totals, there may be a time-series disruption for small areas
with the vintage 2009 data. CB transitioned from having county-level control totals to
having sub-county control totals. And that's likely to cause weird time-series breaks
for some cities where population was previously under- (or over-)estimated.
... Expect more fun this Fall, when vintage 2010 ACS are re-benchmarked to 2010 Census
Enumeration
________________________
Todd Graham
Principal Forecaster
Metropolitan Council
390 Robert Street North
Saint Paul, MN 55101
ph: 651/602-1322
email: todd.graham(a)metc.state.mn.us
in: www.linkedin.com/in/toddgraham
web: www.metrocouncil.org
________________________
________________________________________
From: ctpp-news-bounces(a)chrispy.net [ctpp-news-bounces(a)chrispy.net] On Behalf Of Frank
Lenk [FLENK(a)MARC.ORG]
Sent: Tuesday, February 01, 2011 10:34 PM
To: ctpp-news(a)chrispy.net
Subject: RE: [CTPP] 2000 and 2006-08 work trip comparison question.
Call me dense, but I don’t see how this problem is any different than working with moving
averages. I mean, I do understand that this data is not an average but a period estimate.
Still, the issues created by dropping the first year of the period and adding the last
year as the data series moves forward in time seems the same to me.
What am I not understanding properly?
Frank
Frank Lenk
Director of Research Services
Mid-America Regional Council
600 Broadway, Suite 200
Kansas City, MO 64105
www.marc.org<http://www.marc.org>
816.474.4240
flenk@marc.org<mailto:flenk@marc.org>
816.701.8237
From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces@chrispy.net] On Behalf Of
Patty Becker
Sent: Tuesday, February 01, 2011 3:17 PM
To: ctpp-news(a)chrispy.net
Subject: Re: [CTPP] 2000 and 2006-08 work trip comparison question.
If you see the point about the problem of comparing overlapping 3 year ACS estimates, it
gets even worse with consecutive 5 year numbers, in which 4 of the 5 years are the same
data.
Personally, I think there's a strong argument for releasing 5 year data only twice a
decade, by definition non-overlapping. We may get to that point in a couple of years.
Patty Becker
At 03:53 PM 2/1/2011, you wrote:
Frank-I totally agree and I would like to see the statisticians get involved and think
about this. People are going to compare overlapping periods and we have to get smart about
how to deal with this.
As for why some say we should not compare overlapping years the story goes like this. If
you have 2006 to 2008 data and 2007 to 2009 data you would have two overlapping years.
According to the logic you would in fact only be comparing the first year 2006 to the last
year 2009 as the middle two years would cancel themselves out. While this sounds logical
on the surface there has to be a way to deal with overlapping 5-year periods or it
doesn't make sense to have an ACS.
I am not sure if anyone would out right admit it but is anyone designing performance
measures or other regional metrics calling for tracking annual multi-year period estimates
at tracts or places?
Frank Lenk wrote:
I would also be interested in a more detailed explanation of why we should not compare
overlapping period estimates. From a practical standpoint, people are going to do it
anyway, especially the press. What do we need to know - other than the inherent issues of
what is a statistically significant vs. insignificant change and the fact that ACS was
designed to examine characteristics of the population rather than its level - to be able
to correct naïve interpretations of easily calculated tract-level year-to-year differences
in the estimates of things like poverty rate, unemployment rate, educational attainment
rates, etc.? What is a correct interpretation of these differences?
Frank
Frank Lenk
Director of Research Services
Mid-America Regional Council
600 Broadway, Suite 200
Kansas City, MO 64105
www.marc.org<http://www.marc.org/> <
http://www.marc.org<http://www.marc.org/>>
816.474.4240
flenk(a)marc.org< mailto:flenk@marc.org>
816.701.8237
From: ctpp-news-bounces(a)chrispy.net [ mailto:ctpp-news-bounces@chrispy.net] On Behalf Of
Kendra Watkins
Sent: Monday, January 31, 2011 10:05 AM
To: ctpp-news(a)chrispy.net
Subject: RE: [CTPP] 2000 and 2006-08 work trip comparison question.
This is interesting. I recall hearing this guidance in the past. However on the Census
website on the ACS page it specifically states; "Generally, you can compare American
Community Survey (ACS) 3-year and 5-year estimates with Census 2000 data. There are
differences in the universe, question wording, residence rules, reference periods, and the
way in which the data are tabulated which can impact comparability."
The qualifier in the second sentence addresses the conflict (different methods, time
periods etc) but I can't find anywhere on the ACS pages where the Census recommends we
not compare ACS to decennial Census. And when I search by subject the Journey to Work
topic states that I can 'Compare' it to the 2000 Census.
It does specifically state not to compare overlapping years on multiyear estimates.
Kendra Watkins
Senior Data Analyst
Mid-Region Council of Governments
809 Copper Ave. NW
Albuquerque, NM 87102
Phone: (505)724-3601
Fax: (505)247-1753
Email: kwatkins(a)mrcog-nm.gov< mailto:tgaudette@mrcog-nm.gov>
This email and any files transmitted with it are confidential and intended solely for the
use of the individual or entity to which they are addressed. If you have received this
email in error please notify the system manager. This message contains confidential
information and is intended only for the individual named. If you are not the named
addressee you should not disseminate, distribute or copy this e-mail.
From: ctpp-news-bounces(a)chrispy.net [ mailto:ctpp-news-bounces@chrispy.net] On Behalf Of
Weinberger, Penelope
Sent: Monday, January 31, 2011 8:41 AM
To: ctpp-news(a)chrispy.net
Subject: RE: [CTPP] 2000 and 2006-08 work trip comparison question.
The CB does not recommend comparing an ACS based data set to a CB Long Form based data
set. The 2000 data represent a point in time estimate, the ACS data represent a period
estimate. Furthermore, the Census Bureau recommends not comparing period estimates with
overlapping years.
Penelope Weinberger
CTPP Program Manager
AASHTO
202-624-3556
http://ctpp.transportation.org/Pages/default.aspx
It's just as bad to not make a plan as to blindly follow the one you already have.
From: ctpp-news-bounces(a)chrispy.net [ mailto:ctpp-news-bounces@chrispy.net] On Behalf Of
Seidensticker, Dan
Sent: Friday, January 28, 2011 4:18 PM
To: (ctpp-news(a)chrispy.net)
Subject: [CTPP] 2000 and 2006-08 work trip comparison question.
We downloaded the2006-2008 ACS county-to-county worker flow for Dane County, Wisconsin
from http://ctpp.transportation.org/Pages/3yrdas.aspx.
The question we now have...can that data be compared to the county-to-county 2000 CTPP
work trips to determine any statistically significant increase/decrease? If so, how
would one calculate the margin of error?
Dan Seidensticker
GIS Specialist
Madison Area Transportation Planning Board:
A Metropolitan Planning Organization (MPO)
City of Madison Planning Unit
121 S. Pinckney Street, Suite 400
Madison, WI 53703
Voice: 608-266-9119
Fax: 608-261-9967
Email: dseidensticker(a)cityofmadison.com< mailto:dseidensticker@cityofmadison.com>
www.MadisonAreaMPO.org<http://www.madisonareampo.org/> <
http://www.madisonareampo.org/>
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Ed Christopher
708-283-3534 (V)
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Matteson, IL 60443
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-------------------------------------------------------------------------------------------------
Patricia C. (Patty) Becker 248/354-6520
APB Associates/SEMCC FAX 248/354-6645
28300 Franklin Road Home 248/355-2428
Southfield, MI 48034 pbecker(a)umich.edu
2 Feb
2 Feb
11:49 a.m.
New subject: how to know if Census ests and ACS have been under-estimating the population?
After sending an earlier CTPP post this morning, I was asked "how do you know Census
Bureau "badly underestimated" the top-line population totals in your
metro?"
Great question...
The latest news is: Census Bureau has coughed up the answer for us. This morning CB has
published side-by-side comparison of Census enumeration counts vs. the Bureau's annual
estimates (from a model). You can find it at
http://www.census.gov/popest/states/tables/table-2.xls
It looks like there are 26 states where the Bureau's model has been under-estimating
population by > 0.5%.
And 10 states where the model has been over-estimating population by > 0.5%.
* Of course, my tally here assumes that the Census counts are "perfect" and free
of under-count. And maybe it's too early to make such assumption. (Biggest
discrepancy: Arizona... Hmm.)
Anyway, check it out at http://www.census.gov/popest/states/tables/table-2.xls
Enjoy.
________________________
Todd Graham
Principal Forecaster
Metropolitan Council
390 Robert Street North
Saint Paul, MN 55101
ph: 651/602-1322
email: todd.graham(a)metc.state.mn.us
in: www.linkedin.com/in/toddgraham
web: http://www.metrocouncil.org/data/
________________________
-----Original Message-----
From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces@chrispy.net] On Behalf Of
Graham, Todd
Sent: Wednesday, February 02, 2011 8:47 AM
To: ctpp-news(a)chrispy.net
Subject: RE: [CTPP] 2000 and 2006-08 work trip comparison question
Hi Frank--
Hope the new year is treating you well.
You asked what you're missing: How is the 3-year or 5-year window *not* like a moving
average?
Some of the moving parts changing from year to year are the control totals and, as result,
the weights (expansion factor) that would be attached to any given household found in the
5 annual sub-samples that comprise the period sample.
The population control totals come an exogenous, completely-outside-the-survey-itself,
annual estimation model. And in our region, Mpls-St Paul, CB badly underestimated the
top-line population totals during early and mid-decade. I think they realized it (oops),
and they've been trying to make up ground ever since.
Also pertaining to control totals, there may be a time-series disruption for small areas
with the vintage 2009 data. CB transitioned from having county-level control totals to
having sub-county control totals. And that's likely to cause weird time-series breaks
for some cities where population was previously under- (or over-)estimated.
... Expect more fun this Fall, when vintage 2010 ACS are re-benchmarked to 2010 Census
Enumeration
________________________
Todd Graham
Principal Forecaster
Metropolitan Council
390 Robert Street North
Saint Paul, MN 55101
ph: 651/602-1322
email: todd.graham(a)metc.state.mn.us
in: www.linkedin.com/in/toddgraham
web: www.metrocouncil.org
________________________
________________________________________
From: ctpp-news-bounces(a)chrispy.net [ctpp-news-bounces(a)chrispy.net] On Behalf Of Frank
Lenk [FLENK(a)MARC.ORG]
Sent: Tuesday, February 01, 2011 10:34 PM
To: ctpp-news(a)chrispy.net
Subject: RE: [CTPP] 2000 and 2006-08 work trip comparison question.
Call me dense, but I don't see how this problem is any different than working with
moving averages. I mean, I do understand that this data is not an average but a period
estimate. Still, the issues created by dropping the first year of the period and adding
the last year as the data series moves forward in time seems the same to me.
What am I not understanding properly?
Frank
Frank Lenk
Director of Research Services
Mid-America Regional Council
600 Broadway, Suite 200
Kansas City, MO 64105
www.marc.org<http://www.marc.org>
816.474.4240
flenk@marc.org<mailto:flenk@marc.org>
816.701.8237
12:04 p.m.
New subject: how to know if Census ests and ACS have been under-estimating the population?
A huge improvement from 2000, when the under-estimation of the population
was about 3 percent nationally (as I recall, about 274 v 281 million).
On Wed, Feb 2, 2011 at 5:49 PM, Graham, Todd
<todd.graham(a)metc.state.mn.us>wrote;wrote:
After sending an earlier CTPP post this morning, I
was asked “*how do you
know Census Bureau “badly underestimated” the top-line population totals in
your metro?*”
Great question…
The latest news is: Census Bureau has coughed up the answer for us. This
morning CB has published side-by-side comparison of Census enumeration
counts vs. the Bureau’s annual estimates (from a model). You can find it at
http://www.census.gov/popest/states/tables/table-2.xls
It looks like there are 26 states where the Bureau’s model has been
under-estimating population by > 0.5%.
And 10 states where the model has been over-estimating population by >
0.5%.
* Of course, my tally here assumes that the Census counts are “perfect” and
free of under-count. And maybe it’s too early to make such assumption.
(Biggest discrepancy: Arizona… Hmm.)
Anyway, check it out at
http://www.census.gov/popest/states/tables/table-2.xls
Enjoy.
________________________
Todd Graham
Principal Forecaster
Metropolitan Council
390 Robert Street North
Saint Paul, MN 55101
ph: 651/602-1322
email: todd.graham(a)metc.state.mn.us
in: www.linkedin.com/in/toddgraham
web: http://www.metrocouncil.org/data/
________________________
-----Original Message-----
From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces@chrispy.net]
On Behalf Of Graham, Todd
Sent: Wednesday, February 02, 2011 8:47 AM
To: ctpp-news(a)chrispy.net
Subject: RE: [CTPP] 2000 and 2006-08 work trip comparison question
Hi Frank--
Hope the new year is treating you well.
You asked what you're missing: How is the 3-year or 5-year window *not*
like a moving average?
Some of the moving parts changing from year to year are the control totals
and, as result, the weights (expansion factor) that would be attached to any
given household found in the 5 annual sub-samples that comprise the period
sample.
The population control totals come an exogenous,
completely-outside-the-survey-itself, annual estimation model. And in our
region, Mpls-St Paul, CB badly underestimated the top-line population totals
during early and mid-decade. I think they realized it (oops), and they've
been trying to make up ground ever since.
Also pertaining to control totals, there may be a time-series disruption
for small areas with the vintage 2009 data. CB transitioned from having
county-level control totals to having sub-county control totals. And that's
likely to cause weird time-series breaks for some cities where population
was previously under- (or over-)estimated.
... Expect more fun this Fall, when vintage 2010 ACS are re-benchmarked to
2010 Census Enumeration
________________________
Todd Graham
Principal Forecaster
Metropolitan Council
390 Robert Street North
Saint Paul, MN 55101
ph: 651/602-1322
email: todd.graham(a)metc.state.mn.us
in: www.linkedin.com/in/toddgraham
web: www.metrocouncil.org
________________________
________________________________________
From: ctpp-news-bounces(a)chrispy.net [ctpp-news-bounces(a)chrispy.net] On
Behalf Of Frank Lenk [FLENK(a)MARC.ORG]
Sent: Tuesday, February 01, 2011 10:34 PM
To: ctpp-news(a)chrispy.net
Subject: RE: [CTPP] 2000 and 2006-08 work trip comparison question.
Call me dense, but I don’t see how this problem is any different than
working with moving averages. I mean, I do understand that this data is not
an average but a period estimate. Still, the issues created by dropping the
first year of the period and adding the last year as the data series moves
forward in time seems the same to me.
What am I not understanding properly?
Frank
Frank Lenk
Director of Research Services
Mid-America Regional Council
600 Broadway, Suite 200
Kansas City, MO 64105
www.marc.org<http://www.marc.org>
816.474.4240
flenk@marc.org<mailto:flenk@marc.org>
816.701.8237
_______________________________________________
ctpp-news mailing list
ctpp-news(a)chrispy.net
http://www.chrispy.net/mailman/listinfo/ctpp-news
--
--
Wendell Cox
Demographia | Wendell Cox Consultancy - St. Louis Missouri-Illinois
metropolitan region
Visiting Professor, Conservatoire National des Arts et Metiers, Paris
+1.618 632 8507
www.demographia.com | www.publicpurpose.com | www.rentalcartours.net
Books & Publications
WAR ON THE DREAM: How Anti-Sprawl Policy Threatens the Quality of Life
http://www.demographia.com/wod1.pdf
6th ANNUAL DEMOGRAPHIA INTERNATIONAL HOUSING AFFORDABILITY SURVEY (
http://www.demographia.com/dhi.pdf)
THE WAL-MART REVOLUTION: How Big-Box Stores Benefit Consumers, Workers, and
the Economy
By Richard Vedder & Wendell Cox
3 Feb
3 Feb
9:22 a.m.
New subject: how to know if Census ests and ACS have been under-estimating the population?
The great dilemma in 2000 was the immigrant undercount - it was exacerbated
by returning to the modes for the years right after 2000 so we had a mammoth
growth rate from 1999 to 2000 and then back business not as usual as I
recall. AEP
From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces@chrispy.net]
On Behalf Of wendell cox
Sent: Wednesday, February 02, 2011 1:04 PM
To: ctpp-news(a)chrispy.net
Subject: Re: [CTPP] how to know if Census ests and ACS have been
under-estimating the population?
A huge improvement from 2000, when the under-estimation of the population
was about 3 percent nationally (as I recall, about 274 v 281 million).
On Wed, Feb 2, 2011 at 5:49 PM, Graham, Todd <todd.graham(a)metc.state.mn.us>
wrote:
After sending an earlier CTPP post this morning, I was asked "how do you
know Census Bureau "badly underestimated" the top-line population totals in
your metro?"
Great question.
The latest news is: Census Bureau has coughed up the answer for us. This
morning CB has published side-by-side comparison of Census enumeration
counts vs. the Bureau's annual estimates (from a model). You can find it at
http://www.census.gov/popest/states/tables/table-2.xls
It looks like there are 26 states where the Bureau's model has been
under-estimating population by > 0.5%.
And 10 states where the model has been over-estimating population by > 0.5%.
* Of course, my tally here assumes that the Census counts are "perfect" and
free of under-count. And maybe it's too early to make such assumption.
(Biggest discrepancy: Arizona. Hmm.)
Anyway, check it out at
http://www.census.gov/popest/states/tables/table-2.xls
Enjoy.
________________________
Todd Graham
Principal Forecaster
Metropolitan Council
390 Robert Street North
Saint Paul, MN 55101
ph: 651/602-1322
email: todd.graham(a)metc.state.mn.us
in: www.linkedin.com/in/toddgraham
web: http://www.metrocouncil.org/data/
________________________
-----Original Message-----
From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces@chrispy.net]
On Behalf Of Graham, Todd
Sent: Wednesday, February 02, 2011 8:47 AM
To: ctpp-news(a)chrispy.net
Subject: RE: [CTPP] 2000 and 2006-08 work trip comparison question
Hi Frank--
Hope the new year is treating you well.
You asked what you're missing: How is the 3-year or 5-year window *not* like
a moving average?
Some of the moving parts changing from year to year are the control totals
and, as result, the weights (expansion factor) that would be attached to any
given household found in the 5 annual sub-samples that comprise the period
sample.
The population control totals come an exogenous,
completely-outside-the-survey-itself, annual estimation model. And in our
region, Mpls-St Paul, CB badly underestimated the top-line population totals
during early and mid-decade. I think they realized it (oops), and they've
been trying to make up ground ever since.
Also pertaining to control totals, there may be a time-series disruption for
small areas with the vintage 2009 data. CB transitioned from having
county-level control totals to having sub-county control totals. And that's
likely to cause weird time-series breaks for some cities where population
was previously under- (or over-)estimated.
... Expect more fun this Fall, when vintage 2010 ACS are re-benchmarked to
2010 Census Enumeration
________________________
Todd Graham
Principal Forecaster
Metropolitan Council
390 Robert Street North
Saint Paul, MN 55101
ph: 651/602-1322
email: todd.graham(a)metc.state.mn.us
in: www.linkedin.com/in/toddgraham
web: www.metrocouncil.org
________________________
________________________________________
From: ctpp-news-bounces(a)chrispy.net [ctpp-news-bounces(a)chrispy.net] On
Behalf Of Frank Lenk [FLENK(a)MARC.ORG]
Sent: Tuesday, February 01, 2011 10:34 PM
To: ctpp-news(a)chrispy.net
Subject: RE: [CTPP] 2000 and 2006-08 work trip comparison question.
Call me dense, but I don't see how this problem is any different than
working with moving averages. I mean, I do understand that this data is not
an average but a period estimate. Still, the issues created by dropping the
first year of the period and adding the last year as the data series moves
forward in time seems the same to me.
What am I not understanding properly?
Frank
Frank Lenk
Director of Research Services
Mid-America Regional Council
600 Broadway, Suite 200
Kansas City, MO 64105
www.marc.org<http://www.marc.org>
816.474.4240
flenk@marc.org<mailto:flenk@marc.org>
816.701.8237
_______________________________________________
ctpp-news mailing list
ctpp-news(a)chrispy.net
http://www.chrispy.net/mailman/listinfo/ctpp-news
--
--
Wendell Cox
Demographia | Wendell Cox Consultancy - St. Louis Missouri-Illinois
metropolitan region
Visiting Professor, Conservatoire National des Arts et Metiers, Paris
+1.618 632 8507
www.demographia.com | www.publicpurpose.com | www.rentalcartours.net
Books & Publications
WAR ON THE DREAM: How Anti-Sprawl Policy Threatens the Quality of Life
http://www.demographia.com/wod1.pdf
6th ANNUAL DEMOGRAPHIA INTERNATIONAL HOUSING AFFORDABILITY SURVEY
(http://www.demographia.com/dhi.pdf)
THE WAL-MART REVOLUTION: How Big-Box Stores Benefit Consumers, Workers, and
the Economy
By Richard Vedder & Wendell Cox
4828
days inactive
4829
days old
3 comments
3 participants
participants (3)
-
Alan -
Graham, Todd -
wendell cox