Hello,
Brian Chenault from the Hampton Roads Transportation Planning Organization here. We are trying to collect several pieces of data at the block group level using 2007-2011 ACS 5-year estimates. Using the Census' Summary File Excel Retrieval Tool, we are able to retrieve basic population data at the block group level. However, data at the block group level is not provided for poverty, language spoken at home, etc. This appeared to be the case even when examining 2006-2010/2005-2009 5-year estimates. Has this information not been "filtered down" from the census tract level yet? How is one supposed to go about gathering this type of updated information at the block group level?
Much appreciated,
Brian
[Description: Description: Description: Description: Description: TPO-Heartbeat-Logo-FINAL]<http://www.hrtpo.org/>
Brian Chenault
Community Outreach Planner
Hampton Roads Transportation Planning Organization
The Regional Building | 723 Woodlake Drive | Chesapeake, Virginia | 23320
bchenault(a)hrpdcva.gov<mailto:bchenault(a)hrpdcva.gov> | http://www.hrtpo.org<http://www.hrtpo.org/> | Phone: 757.420.8300 | Fax: 757.523.4881
Fellow CTPP afficionados:
The MOE reported by Census is based on a 90% confidence interval, which
is a common standard for scientific research -- it means that the
confidence interval has a 90% likelihood of including the real value
(aka 9 to 1 odds). The larger the MOE in relation to the estimated
value, the less reliable the estimate. Relatively large MOEs do not
necessarily mean the estimates are "worthless," as Ed notes. It all
depends on your needs and purposes.
It is good to strive for scientific certainty. But in the world of
public policy-making, transportation planning, etc., we normally are
obliged to make decisions with whatever is the best available data. We
can't usually throw up our hands in despair if scientific certainty is
not available. I'm retired now, but what I used to do when confronted
with this quandary was to calculate just exactly how unreliable an
estimate was before deciding what to do about it.
A quick and dirty alternate way to look at it is to divide the MOE by
1.645 to get the Standard Error of the Estimate (SEE). The SEE
represents the standard deviation around the estimate, which has a 68%
likelihood of including the real value, or about 2 to 1 odds. If you
look at the estimate and its SEE rather than its MOE, are you willing
to take a deep breath and make needed decisions based on 2 to 1 odds,
rather than wait for 9 to 1 odds?
For another example, I might have a number from ACS or PUMS that wasn't
significant at the 90% confidence level (e.g., has commuting between
county A and county B actually gone up between year x and year y, or is
it more accurate to say it was stable?). Using a standard built-in
formula in Excel (NORMDIST) I could determine that the increase was
significant at the 80% level. From my point of view, 80% confidence
(or maybe even 70%) might be fine, depending on the nature of the
question. Your mileage may vary.
--
Pete Swensson
retired from Thurston Regional Planning Council
Olympia, WA
Quoting Ed Christopher :
Do we have a metric for useless? I have seen published data
where the MOE is more than 85% of the estimate. Is this useless? What
if the MOE is only 10% of the estimate. Anyone using any standards for
what is considered useless. Also, at what point should this
determination be put in the hands of the user/analyst?
Ed C
On Feb 15, 2013, at 9:33 PM, Patricia Becker
wrote:
Brian,
Tell me something. Do you want to use these data for individual block
groups or do you want to aggregate BGs to larger areas, such as TAZs?
I hope you know that the sampling errors for single BG data are so high
as to render the data absolutely useless. I think that's why you can't
find the numbers.
Patty Becker
On Fri, Feb 15, 2013 at 3:35 PM, Brian Chenault wrote:
Hello,
Brian Chenault from the Hampton Roads Transportation Planning
Organization here. We are trying to collect several pieces of data at
the block group level using 2007-2011 ACS 5-year estimates. Using the
Census’ Summary File Excel Retrieval Tool, we are able to retrieve
basic population data at the block group level. However, data at the
block group level is not provided for poverty, language spoken at home,
etc. This appeared to be the case even when examining
2006-2010/2005-2009 5-year estimates. Has this information not been
“filtered down” from the census tract level yet? How is one
supposed to go about gathering this type of updated information at the
block group level?
Much appreciated,
Brian
Brian Chenault
Community Outreach Planner
Hampton Roads Transportation Planning Organization
The Regional Building | 723 Woodlake Drive | Chesapeake, Virginia | 23320
bchenault(a)hrpdcva.gov | http://www.hrtpo.org | Phone: 757.420.8300 |
Fax: 757.523.4881
_______________________________________________
ctpp-news mailing list
ctpp-news(a)ryoko.chrispy.nethttp://ryoko.chrispy.net/mailman/listinfo/ctpp-news
--
Patricia C. (Patty) Becker
APB Associates/Southeast Michigan Census Council (SEMCC)
28300 Franklin Rd, Southfield, MI 48034
office: 248-354-6520
home:248-355-2428
pbecker(a)umich.edu
_______________________________________________
ctpp-news mailing list
ctpp-news(a)ryoko.chrispy.nethttp://ryoko.chrispy.net/mailman/listinfo/ctpp-news
-------------------------
_______________________________________________
ctpp-news mailing list
ctpp-news(a)ryoko.chrispy.nethttp://ryoko.chrispy.net/mailman/listinfo/ctpp-news
Do we have a metric for useless? I have seen published data where the MOE is more than 85% of the estimate. Is this useless? What if the MOE is only 10% of the estimate. Anyone using any standards for what is considered useless. Also, at what point should this determination be put in the hands of the user/analyst?
Ed C
On Feb 15, 2013, at 9:33 PM, Patricia Becker <pbecker(a)umich.edu> wrote:
> Brian,
>
> Tell me something. Do you want to use these data for individual block groups or do you want to aggregate BGs to larger areas, such as TAZs? I hope you know that the sampling errors for single BG data are so high as to render the data absolutely useless. I think that's why you can't find the numbers.
>
> Patty Becker
>
> On Fri, Feb 15, 2013 at 3:35 PM, Brian Chenault <bchenault(a)hrtpo.org> wrote:
>> Hello,
>>
>>
>>
>> Brian Chenault from the Hampton Roads Transportation Planning Organization here. We are trying to collect several pieces of data at the block group level using 2007-2011 ACS 5-year estimates. Using the Census’ Summary File Excel Retrieval Tool, we are able to retrieve basic population data at the block group level. However, data at the block group level is not provided for poverty, language spoken at home, etc. This appeared to be the case even when examining 2006-2010/2005-2009 5-year estimates. Has this information not been “filtered down” from the census tract level yet? How is one supposed to go about gathering this type of updated information at the block group level?
>>
>>
>>
>> Much appreciated,
>>
>>
>>
>> Brian
>>
>>
>>
>> <image001.png>
>>
>>
>>
>> Brian Chenault
>>
>> Community Outreach Planner
>>
>> Hampton Roads Transportation Planning Organization
>>
>> The Regional Building | 723 Woodlake Drive | Chesapeake, Virginia | 23320
>>
>> bchenault(a)hrpdcva.gov | http://www.hrtpo.org | Phone: 757.420.8300 | Fax: 757.523.4881
>>
>>
>>
>>
>>
>>
>> _______________________________________________
>> ctpp-news mailing list
>> ctpp-news(a)ryoko.chrispy.net
>> http://ryoko.chrispy.net/mailman/listinfo/ctpp-news
>
>
>
> --
> Patricia C. (Patty) Becker
> APB Associates/Southeast Michigan Census Council (SEMCC)
> 28300 Franklin Rd, Southfield, MI 48034
> office: 248-354-6520
> home:248-355-2428
> pbecker(a)umich.edu
> _______________________________________________
> ctpp-news mailing list
> ctpp-news(a)ryoko.chrispy.net
> http://ryoko.chrispy.net/mailman/listinfo/ctpp-news
This new group may be of interest to some.
With funding from the U.S. Census Bureau, the Population Reference
Bureau (PRB) and Sabre Systems are forming a new American Community
Survey (ACS) Data Users Group. The purpose of the ACS Data Users Group
is to improve understanding of the value and utility of ACS data.
Membership in the group is free and open to all interested ACS data
users. The ACS Data Users Group will not play a role in advising the
Census Bureau or advocating to the Census Bureau on behalf of ACS data
users. The group is led by a Steering Committee, of which I am a member,
that represents a broad spectrum of data users with different interests.
To facilitate communication among ACS data users, PRB and Sabre Systems
will create and maintain an online forum, organize webinars and special
sessions at professional meetings, and hold an annual ACS Data Users
Conference. The online forum is the centerpiece of this project and will
provide a discussion site where people can share messages, materials,
and announcements related to ACS data and methods. Specific activities
and topics will be determined based on input from ACS Data Users Group
members, Steering Committee members, and Census Bureau staff.
To collect information about activities and topics of interest to ACS
data users, and to start assembling a preliminary list of ACS Data Users
Group members, the Steering Committee has created a brief survey
questionnaire (http://www.surveymonkey.com/s/ACSDataUsers). The survey
takes about 10-15 minutes to complete. Individual responses will be kept
confidential; only the aggregate data will be reported. Please respond
by March 8. If you have any questions about the survey, please contact
Mark Mather, Associate Vice President of Domestic Programs at the
Population Reference Bureau at mmather(a)prb.org or 202-939-5433.
Thank you for your time!
--
Ed Christopher
708-283-3534 (V)
708-574-8131 (cell)
FHWA RC-TST-PLN
4749 Lincoln Mall Drive, Suite 600
Matteson, IL 60443
Apologies for cross posting, but we want wide distribution...
Hi All
Here is a link to download the newly released RFP from the CTPP Program to assess the utility of the upcoming release of five-year CTPP data. Please click the link and download the RFP if you are interested in performing this research. Please forward this email as appropriate.
http://ctpp.transportation.org/Pages/default.aspx
Thanks!
Penelope Z. Weinberger
CTPP Program Manager
AASHTO
202-624-3556
ctpp.transportation.org
Is there any information about production of the CTTP or the county-to-county commuting flows more than once every ten years? Since they are based on the annual ACS there is an opportunity for more frequent updates than in the past. What are the current plans?
Dan Estersohn
Senior Demographer
Arbitron Inc
9705 Patuxent Woods Drive
Columbia, MD 21046
410-312-8434
Dan.Estersohn(a)Arbitron.com
For those that missed Census sub-committee at TRB last month, the
presentations can be found online here:
http://trbcensus.com/notes.html
With the release of the new CTPP data and the continuing ACS releases, we
are looking forward to exciting things in the next few years. Please make
note of any work you are doing with the new data. We want to hear from you
next year!
*Mara Kaminowitz, GISP
*GIS Analyst
.........................................................................
*Baltimore Metropolitan Council*
Offices @ McHenry Row
1500 Whetstone Way
Suite 300
Baltimore, MD 21230
410-732-0500 ext. 1030
mkaminowitz(a)baltometro.orgwww.baltometro.org
