15 Mar
2012
15 Mar
'12
12:23 p.m.
Hello,
I need to get a regional estimate and MOE composed of 6 counties. I know the
rule of thumb is that aggregating MOE's doesn't work well for more than 4
units. Does anyone know is using 6 would cause the MOE to be inaccurate?
Mara Kaminowitz
GIS Analyst
.........................................................................
Baltimore Metropolitan Council
Offices at McHenry Row
1500 Whetstone Way
Suite 300
Baltimore, MD 21230
410-732-0500 ext. 1030
<mailto:mkaminowitz(a)baltometro.org> mkaminowitz(a)baltometro.org
<http://www.baltometro.org/> www.baltometro.org
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16 Mar
16 Mar
8:59 a.m.
Mara--Let me know if you hear anything. I think this is a very
perplexing question and worthy of some research under the banner of "how
to work with ACS data, tips and tricks".
Attached is something I did that might give you "a little" insight. On
the attached slide I had a block group table with 5 different modes to
work, the Total Population and Total Workers. What I wanted to do was
to figure out the total number of commuters along with the MOE. Remember
Census does not give us the Total Commuters with the block group data.
Doing the math to get Total Commuters was easy, just add up the modes.
However, the MOE became something of a guessing game. I first used the
formula for for calculating the MOE for more than two estimates. I got
one number 214 (with 4 variables) or 245 (with 5 variables) depending if
you used the MOE associated with a cell that had zero observations.
Dealing with zero cells in ACS brings its own issues and questions.
I then realized that the total commuters was actually the difference
between the Total Workers and those who Worked at Home, only two
variables. That allowed me to use a different MOE formula (which by the
way is the same even though I was subtracting values instead of adding)
and I got 209.
My point is that although small with only 4 variables I was introducing
some additional error by increasing the number of variables. Exactly
how much I wasn't sure. If I did not consider the zero cell MOE
influence, the added error was in the neighborhood of 2.3%. So what I
found is that as you increase variables your MOE calculation would then
have an additional MOE. Hey a new statistic, the MOE of the MOE.
What I could have done is a few more Block Groups and found some with no
zero values so that I could see what 5 variables as opposed to 4 did but
that is where I think this is worthy of research by someone with a
statical mind.
mkaminowitz(a)baltometro.org wrote:
Hello,
I need to get a regional estimate and MOE composed of 6 counties. I know
the rule of thumb is that aggregating MOE's doesn't work well for more
than 4 units. Does anyone know is using 6 would cause the MOE to be
inaccurate?
*Mara Kaminowitz
*GIS Analyst
.........................................................................
*Baltimore Metropolitan Council*
Offices at McHenry Row
1500 Whetstone Way
Suite 300
Baltimore, MD 21230
410-732-0500 ext. 1030
mkaminowitz(a)baltometro.org <mailto:mkaminowitz(a)baltometro.org>
www.baltometro.org
<http://www.baltometro.org/>__
------------------------------------------------------------------------
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--
Ed Christopher
708-283-3534 (V)
708-574-8131 (cell)
FHWA RC-TST-PLN
4749 Lincoln Mall Drive, Suite 600
Matteson, IL 60443
11:09 a.m.
Ed,
Working with any one block group almost anywhere in the county
(Manhattan comes to mind as a possible exception) will have such high
MOEs that the data are not worth anything, must less your time! There
just are not enough interviews in a single block group of, on the
average, 300 housing units, even over five years, to produce decent
data. The only point of making BG data available is for aggregation,
especially in the radius analyses so popular in the private sector.
Patty Becker
At 08:59 AM 3/16/2012, you wrote:
Mara--Let me know if you hear anything. I think this
is a very
perplexing question and worthy of some research under the banner of
"how to work with ACS data, tips and tricks".
Attached is something I did that might give you "a little"
insight. On the attached slide I had a block group table with 5
different modes to work, the Total Population and Total
Workers. What I wanted to do was to figure out the total number of
commuters along with the MOE. Remember Census does not give us the
Total Commuters with the block group data. Doing the math to get
Total Commuters was easy, just add up the modes. However, the MOE
became something of a guessing game. I first used the formula for
for calculating the MOE for more than two estimates. I got one
number 214 (with 4 variables) or 245 (with 5 variables) depending if
you used the MOE associated with a cell that had zero observations.
Dealing with zero cells in ACS brings its own issues and questions.
I then realized that the total commuters was actually the difference
between the Total Workers and those who Worked at Home, only two
variables. That allowed me to use a different MOE formula (which by
the way is the same even though I was subtracting values instead of
adding) and I got 209.
My point is that although small with only 4 variables I was
introducing some additional error by increasing the number of
variables. Exactly how much I wasn't sure. If I did not consider
the zero cell MOE influence, the added error was in the neighborhood
of 2.3%. So what I found is that as you increase variables your MOE
calculation would then have an additional MOE. Hey a new statistic,
the MOE of the MOE.
What I could have done is a few more Block Groups and found some
with no zero values so that I could see what 5 variables as opposed
to 4 did but that is where I think this is worthy of research by
someone with a statical mind.
mkaminowitz(a)baltometro.org wrote:
-------------------------------------------------------------------------------------------------
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
Hello,
I need to get a regional estimate and MOE composed of 6 counties. I
know the rule of thumb is that aggregating MOE's doesn't work well
for more than 4 units. Does anyone know is using 6 would cause the
MOE to be inaccurate?
*Mara Kaminowitz
*GIS Analyst
.........................................................................
*Baltimore Metropolitan Council*
Offices at McHenry Row
1500 Whetstone Way
Suite 300
Baltimore, MD 21230
410-732-0500 ext. 1030
mkaminowitz(a)baltometro.org <mailto:mkaminowitz(a)baltometro.org>
www.baltometro.org
<http://www.baltometro.org/>__
------------------------------------------------------------------------
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This message may contain legally privileged and confidential
information that is intended only for the use of the recipient(s)
named above. If you are not an intended recipient, taking any
action based on the contents of this message is strictly
prohibited. Please immediately notify the sender if you have
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--
Ed Christopher
708-283-3534 (V)
708-574-8131 (cell)
FHWA RC-TST-PLN
4749 Lincoln Mall Drive, Suite 600
Matteson, IL 60443
_______________________________________________
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11:47 a.m.
Patty the example was to show issues of aggregation not to talk about
one Block Group. The reason the Block Group using mode was used was for
my exercise was because I could identify the difference in the MOE that
was calculated using 4 and 5 variables verse 2 variables to get the same
MOE. Are there any relationships in the MOE noise that we can develop
as we aggregate variables together?
I did liked Cemal's idea of doing a stepwise approach in aggregating in
a few variable at a time. Looking at the effects of doing this could
prove interesting. If anyone has tried this please share what you have
seen or learn. I think we are all learning here.
Patty Becker wrote:
Ed,
Working with any one block group almost anywhere in the county
(Manhattan comes to mind as a possible exception) will have such high
MOEs that the data are not worth anything, must less your time! There
just are not enough interviews in a single block group of, on the
average, 300 housing units, even over five years, to produce decent
data. The only point of making BG data available is for aggregation,
especially in the radius analyses so popular in the private sector.
Patty Becker
At 08:59 AM 3/16/2012, you wrote:
--
Ed Christopher
708-283-3534 (V)
708-574-8131 (cell)
FHWA RC-TST-PLN
4749 Lincoln Mall Drive, Suite 600
Matteson, IL 60443
Mara--Let me know if you hear anything. I think
this is a very
perplexing question and worthy of some research under the banner of
"how to work with ACS data, tips and tricks".
Attached is something I did that might give you "a little" insight.
On the attached slide I had a block group table with 5 different modes
to work, the Total Population and Total Workers. What I wanted to do
was to figure out the total number of commuters along with the MOE.
Remember Census does not give us the Total Commuters with the block
group data. Doing the math to get Total Commuters was easy, just add
up the modes. However, the MOE became something of a guessing game. I
first used the formula for for calculating the MOE for more than two
estimates. I got one number 214 (with 4 variables) or 245 (with 5
variables) depending if you used the MOE associated with a cell that
had zero observations. Dealing with zero cells in ACS brings its own
issues and questions.
I then realized that the total commuters was actually the difference
between the Total Workers and those who Worked at Home, only two
variables. That allowed me to use a different MOE formula (which by
the way is the same even though I was subtracting values instead of
adding) and I got 209.
My point is that although small with only 4 variables I was
introducing some additional error by increasing the number of
variables. Exactly how much I wasn't sure. If I did not consider the
zero cell MOE influence, the added error was in the neighborhood of
2.3%. So what I found is that as you increase variables your MOE
calculation would then have an additional MOE. Hey a new statistic,
the MOE of the MOE.
What I could have done is a few more Block Groups and found some with
no zero values so that I could see what 5 variables as opposed to 4
did but that is where I think this is worthy of research by someone
with a statical mind.
mkaminowitz(a)baltometro.org wrote:
-------------------------------------------------------------------------------------------------
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
------------------------------------------------------------------------
_______________________________________________
ctpp-news mailing list
ctpp-news(a)ryoko.chrispy.net
http://ryoko.chrispy.net/mailman/listinfo/ctpp-news Hello,
I need to get a regional estimate and MOE composed of 6 counties. I
know the rule of thumb is that aggregating MOE's doesn't work well
for more than 4 units. Does anyone know is using 6 would cause the
MOE to be inaccurate?
*Mara Kaminowitz
*GIS Analyst
.........................................................................
*Baltimore Metropolitan Council*
Offices at McHenry Row
1500 Whetstone Way
Suite 300
Baltimore, MD 21230
410-732-0500 ext. 1030
mkaminowitz(a)baltometro.org < mailto:mkaminowitz(a)baltometro.org>
www.baltometro.org <http://www.baltometro.org/>
< http://www.baltometro.org/>__
------------------------------------------------------------------------
*Confidentiality Statement*
This message may contain legally privileged and confidential
information that is intended only for the use of the recipient(s)
named above. If you are not an intended recipient, taking any action
based on the contents of this message is strictly prohibited. Please
immediately notify the sender if you have received this message in error.
------------------------------------------------------------------------
_______________________________________________
ctpp-news mailing list
ctpp-news(a)ryoko.chrispy.net
http://ryoko.chrispy.net/mailman/listinfo/ctpp-news
--
Ed Christopher
708-283-3534 (V)
708-574-8131 (cell)
FHWA RC-TST-PLN
4749 Lincoln Mall Drive, Suite 600
Matteson, IL 60443
_______________________________________________
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ctpp-news(a)ryoko.chrispy.net
http://ryoko.chrispy.net/mailman/listinfo/ctpp-news 
20 Mar
20 Mar
12:33 p.m.
New subject: [CTPP] Census Urbanized Areas and MPO/TMA Designation
Hi,
Can someone provide updates on the release date? I checked Census release calendar up to
Aril. However, I don't see any UZA related release. It is expected in March 12.
Thanks,
Sharon Ju, Ph.D.
Sr. Transportation Analyst
H-GAC
3555 Timmons Ln., Suite 120
Houston, TX 77027
Phone: 713.993.2419
Email: sharon.ju(a)h-gac.com
1:20 p.m.
New subject: [CTPP] Census Urbanized Areas and MPO/TMA Designation
The best information Elaine Murakami and I have is the second half of
March. That would make it anytime. If someone has better information
please pass it along.
Hi,
Can someone provide updates on the release date? I checked Census release
calendar up to Aril. However, I don't see any UZA related release. It is
expected in March 12.
Thanks,
Sharon Ju, Ph.D.
Sr. Transportation Analyst
H-GAC
3555 Timmons Ln., Suite 120
Houston, TX 77027
Phone: 713.993.2419
Email: sharon.ju(a)h-gac.com
_______________________________________________
ctpp-news mailing list
ctpp-news(a)ryoko.chrispy.net
http://ryoko.chrispy.net/mailman/listinfo/ctpp-news
--
Ed Christopher
FHWA Resource Center Planning Team
4749 Lincoln Mall Drive, Suite 600
Matteson, IL 60443
708-283-3534 (V)
708-574-8131 (C)
5:59 p.m.
New subject: [CTPP] Census Urbanized Areas and MPO/TMA Designation
Check the US Census Bureau website, http://www.census.gov/, then select Newsroom, then
News/Release Schedule. March 26 shows a News Release for Updated Urban Areas List.
Jon Hallas
Chicago Metropolitan Agency for Planning.
-----Original Message-----
From: Ed Christopher [mailto:edc(a)berwyned.com]
Sent: Tuesday, March 20, 2012 12:21 PM
To: ctpp-news(a)chrispy.net
Subject: Re: [CTPP] Census Urbanized Areas and MPO/TMA Designation
The best information Elaine Murakami and I have is the second half of March. That would
make it anytime. If someone has better information please pass it along.
Hi,
Can someone provide updates on the release date? I checked Census
release calendar up to Aril. However, I don't see any UZA related
release. It is expected in March 12.
Thanks,
Sharon Ju, Ph.D.
Sr. Transportation Analyst
H-GAC
3555 Timmons Ln., Suite 120
Houston, TX 77027
Phone: 713.993.2419
Email: sharon.ju(a)h-gac.com
_______________________________________________
ctpp-news mailing list
ctpp-news(a)ryoko.chrispy.net
http://ryoko.chrispy.net/mailman/listinfo/ctpp-news
--
Ed Christopher
FHWA Resource Center Planning Team
4749 Lincoln Mall Drive, Suite 600
Matteson, IL 60443
708-283-3534 (V)
708-574-8131 (C)
The information contained in this communication is confidential and may be legally
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This message has been scanned for viruses and other harmful content upon transmission.
1:25 p.m.
New subject: [CTPP] Census Urbanized Areas and MPO/TMA Designation
You know as much as we do at TTI. We expect/hope for some release of information related
to UZA anytime now.
Jonathan Brooks
Assistant Transportation Researcher
Texas Transportation Institute: Transit Mobility Program
Office 713.686.2971 ext 15106
Fax 713.686.5396
Cell 806.440.2462
Email j-brooks(a)ttimail.tamu.edu
-----Original Message-----
From: Ju, Sharon [mailto:sharon.ju(a)h-gac.com]
Sent: Tuesday, March 20, 2012 11:34 AM
To: 'ctpp-news(a)chrispy.net'
Subject: [CTPP] Census Urbanized Areas and MPO/TMA Designation
Hi,
Can someone provide updates on the release date? I checked Census release calendar up to
Aril. However, I don't see any UZA related release. It is expected in March 12.
Thanks,
Sharon Ju, Ph.D.
Sr. Transportation Analyst
H-GAC
3555 Timmons Ln., Suite 120
Houston, TX 77027
Phone: 713.993.2419
Email: sharon.ju(a)h-gac.com
1:50 p.m.
New subject: [CTPP] Census Urbanized Areas and MPO/TMA Designation
http://www.calendarwiz.com/calendars/calendar.php?crd=cens1sample&PHPSE…
Look at March 26th for release of updated urban areas list
Earl T. Haugen
Executive Director
GF-EGF MPO
701-746-2660
________________________________
From: "Brooks, Jonathan" <j-brooks(a)ttimail.tamu.edu>
To: "ctpp-news(a)ryoko.chrispy.net" <ctpp-news(a)ryoko.chrispy.net>;
"'ctpp-news(a)chrispy.net'" <ctpp-news(a)chrispy.net>
Sent: Tuesday, March 20, 2012 12:25 PM
Subject: Re: [CTPP] Census Urbanized Areas and MPO/TMA Designation
You know as much as we do at TTI. We expect/hope for some release of information related
to UZA anytime now.
Jonathan Brooks
Assistant Transportation Researcher
Texas Transportation Institute: Transit Mobility Program
Office 713.686.2971 ext 15106
Fax 713.686.5396
Cell 806.440.2462
Email j-brooks(a)ttimail.tamu.edu
-----Original Message-----
From: Ju, Sharon [mailto:sharon.ju(a)h-gac.com]
Sent: Tuesday, March 20, 2012 11:34 AM
To: 'ctpp-news(a)chrispy.net'
Subject: [CTPP] Census Urbanized Areas and MPO/TMA Designation
Hi,
Can someone provide updates on the release date? I checked Census release calendar up to
Aril. However, I don't see any UZA related release. It is expected in March 12.
Thanks,
Sharon Ju, Ph.D.
Sr. Transportation Analyst
H-GAC
3555 Timmons Ln., Suite 120
Houston, TX 77027
Phone: 713.993.2419
Email: sharon.ju(a)h-gac.com
_______________________________________________
ctpp-news mailing list
ctpp-news(a)ryoko.chrispy.net
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16 Mar
16 Mar
11:01 a.m.
Hi Mara,
Each item that you aggregate will introduce some level of uncertainty
since the exact distribution of aggregated data is not available to you.
We can only estimate the aggregated MOE assuming that each item has
similar statistical distributions.
Since MOE is a function of variance, depending on how much variance there
is in your data, aggregation may produce a confidence interval which can
be reasonable or too large to be useful. You need to evaluate the
reasonableness of the aggregated MOE estimates and associated confidence
intervals. One possible way to start is to aggregate a smaller number of
counties (two or three), add a new one each time, and track the changes
in the MOE estimate.
The following reference has information on how to work with MOEs. I also
added a couple of other links I find useful.
http://www.census.gov/acs/www/Downloads/handbooks/ACSGeneralHandbook.pdf
http://www.census.gov/acs/www/guidance_for_data_users/handbooks/
http://www.census.gov/acs/www/methodology/methodology_main/
Hope this helps.
Best of luck.
Cemal.
Cemal Ayvalik, PhD.
Cambridge Systematics, Inc.
115 South LaSalle Street, Suite 2200
Chicago, IL 60603
tel : 312 665 0209
fax: 312 346 9908
e-mail: cayvalik(a)camsys.com
www.camsys.com
From: <mkaminowitz(a)baltometro.org>
To: <ctpp-news(a)chrispy.net>
Date: 03/15/2012 11:42 AM
Subject: [CTPP] aggregated MOE for 6 counties
Sent by: ctpp-news-bounces(a)chrispy.net
Hello,
I need to get a regional estimate and MOE composed of 6 counties. I know
the rule of thumb is that aggregating MOE's doesn't work well for more
than 4 units. Does anyone know is using 6 would cause the MOE to be
inaccurate?
Mara Kaminowitz
GIS Analyst
.........................................................................
Baltimore Metropolitan Council
Offices at McHenry Row
1500 Whetstone Way
Suite 300
Baltimore, MD 21230
410-732-0500 ext. 1030
mkaminowitz(a)baltometro.org
www.baltometro.org
Confidentiality Statement
This message may contain legally privileged and confidential information
that is intended only for the use of the recipient(s) named above. If you
are not an intended recipient, taking any action based on the contents of
this message is strictly prohibited. Please immediately notify the sender
if you have received this message in error.
_______________________________________________
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days old
ctpp@listserv.transportation.org
10 comments
9 participants
participants (9)
-
Brooks -
Cemal Ayvalik -
Earl Haugen -
Ed Christopher -
Jon Hallas -
Ju -
michael.r.ratcliffe＠census.gov -
mkaminowitz＠baltometro.org -
Patty Becker