Hi, Cliff
The ACS General Guidebook has one chapter devoted to calculating MOEs for
derived estimates. You may find it helpful. I was trying to locate this
document on line, but didn't see it. Attached is my downloaded version
from a while ago.
Liang Long
Cambridge Systematics, Inc.
4800 Hampden Lane
Suite 800
Bethesda, MD 20814
tel 301 347 9141
fax 301 347 0101
FHWA 202-366-6971
e-mail llong(a)camsys.com
www.camsys.com
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Today's Topics:
1. How to Combine Median Values for Mutliple Areas (Cook, Cliff)
2. RE: How to Combine Median Values for Mutliple Areas (Eric Kramer)
----------------------------------------------------------------------
Message: 1
Date: Mon, 3 Jan 2011 13:24:06 -0500
From: "Cook, Cliff" <ccook(a)cambridgema.gov>
Subject: [CTPP] How to Combine Median Values for Mutliple Areas
To: "ctpp-news(a)chrispy.net" <ctpp-news(a)chrispy.net>
Message-ID: <600EBD94B0166D4BADC1083702EC47C4026F6C522B(a)Mordac.City>
Content-Type: text/plain; charset="us-ascii"
I am looking for guidance on how to combine median income values for
several census tracts into a single value and associated margin of error.
I recall seeing something about this topic in an ACS document but cannot
locate the information at this time. Any help would be appreciated.
Cliff Cook
-----------------------------------------------------------------------------
Clifford Cook
Planning Information Manager
Cambridge Community Development Dept.
344 Broadway
Cambridge, MA. 02139
617/349-4656 FAX 617/349-4669 TTY 617/349-4621
email => ccook(a)cambridgema.gov
web site => <http://www.cambridgema.gov/~CDD/>
I listened to your email using DriveCarefully and will respond as soon as I can.
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Sent via BlackBerry from T-Mobile
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Hi, Cliff
Nanda and I just briefly discussed your question on the median value
calculation. We come up with two options:
1. The median income should be available for each Census Tract. You can
take total households for each census tract as weights, using the weighted
average for the median household income across these Census Tracts. Then
MOEs can be calculated using the formula of weighted mean.
2. You can combine the distribution of household incomes for each census
tract and derive a single distribution for aggregated Census tracts. Then
you can come up with a median value.
Using these methods, you will need to interpolate MOEs for the upper bound
and the lower bound.
Both these methods will not give you the real median values - they are
only ballpark figures. But you can definitely try both and see which one
is better.
Liang Long
Cambridge Systematics, Inc.
4800 Hampden Lane
Suite 800
Bethesda, MD 20814
tel 301 347 9141
fax 301 347 0101
FHWA 202-366-6971
e-mail llong(a)camsys.com
www.camsys.com
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01/03/2011 02:39 PM
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Today's Topics:
1. How to Combine Median Values for Mutliple Areas (Cook, Cliff)
2. RE: How to Combine Median Values for Mutliple Areas (Eric Kramer)
----------------------------------------------------------------------
Message: 1
Date: Mon, 3 Jan 2011 13:24:06 -0500
From: "Cook, Cliff" <ccook(a)cambridgema.gov>
Subject: [CTPP] How to Combine Median Values for Mutliple Areas
To: "ctpp-news(a)chrispy.net" <ctpp-news(a)chrispy.net>
Message-ID: <600EBD94B0166D4BADC1083702EC47C4026F6C522B(a)Mordac.City>
Content-Type: text/plain; charset="us-ascii"
I am looking for guidance on how to combine median income values for
several census tracts into a single value and associated margin of error.
I recall seeing something about this topic in an ACS document but cannot
locate the information at this time. Any help would be appreciated.
Cliff Cook
-----------------------------------------------------------------------------
Clifford Cook
Planning Information Manager
Cambridge Community Development Dept.
344 Broadway
Cambridge, MA. 02139
617/349-4656 FAX 617/349-4669 TTY 617/349-4621
email => ccook(a)cambridgema.gov
web site => <http://www.cambridgema.gov/~CDD/>
Does anyone know when the census will release mode of transportation to
work by smaller workplace geographies than place? I was disappointed
that the 2005-2009 ACS didn't have it. Coming up with a work trip mode
split for downtown is something people ask us about all the time.
Thanks.
* * * * * * * * * * * * * * * * * * * * * * * *
Anna Flintoft, PTP
Transportation Planner
Department of Public Works - Transportation Planning and Engineering
City of Minneapolis
Room 301, City of Lakes Building
309 2nd Avenue South
Minneapolis, MN 55401
(612) 673-3885 (office)
(612) 269-9410 (cell)
anna.flintoft(a)ci.minneapolis.mn.us
* * * * * * * * * * * * * * * * * * * * * * * *
Correction to my earlier email: 2005-2009 ACS Block Group data WILL be released on December 14.
From: brian.mckenzie(a)census.gov [mailto:brian.mckenzie@census.gov]
Good Afternoon Mara and Elaine,
The summary file data (block group level data) will be available on December 14th. You can use American Factfinder as a portal. You will be able to download summary file data via the FTP website at <http://www2.census.gov/acs2009_5yr/summaryfile/ <http://www2.census.gov/acs2009_5yr/summaryfile/> >. There will also be a clickable link next to the familiar portion of AFF in which you select the desired ACS year(s) for which you would like data. Hope this helps.
Brian McKenzie
Analyst, Journey to Work and Migration Statistics Branch
U.S. Census Bureau
301-763-6532
brian.mckenzie(a)census.gov
Hi Everyone-- Brian McKenzie at the Census Bureau provided this information on viewing files in Excel to help those of you when you download the tract or block group data from the "summary file" format, instead of the AFF.
Please be sure to share your experiences with analyzing the new 2005-2009 ACS data with the CTPP listserv. Thanks in advance.
Elaine
________________________________
From: brian.mckenzie(a)census.gov [mailto:brian.mckenzie@census.gov]
The Excel-based retrieval tool that I mentioned yesterday can be access via the following page. Once you http://www.census.gov/acs/www/data_documentation/summary_file/ <http://www.census.gov/acs/www/data_documentation/summary_file/> . Below this link is the user guide. You just download the excel file with the macro built into it onto your hard drive, and you can view any SF table in Excel format rather than having to deal with ASCII files.
I was reading the NY Times on my way to work today and found out there are
a serious of articles about ACS2005-2009. The most amazing thing is that
they developed this interactive map at the Census Tract level for the
whole nation. The maps show household income, home value, education and
race and ethnicity at each tract and also the percentage change from the
Census 2000.
Here is the link. You got to check this out!
http://projects.nytimes.com/census/2010/explorer?ref=us
Liang Long
Cambridge Systematics, Inc.
4800 Hampden Lane
Suite 800
Bethesda, MD 20814
tel 301 347 9141
fax 301 347 0101
FHWA 202-366-6971
e-mail llong(a)camsys.com
www.camsys.com
In my opinion, the bureau has absolutely made the
right decision in keeping the block group data
off of AFF. I recommended this course of action
several years ago. The error levels are WAY too
high for casual users, and power users can easily
download the file and do what they need to do.
Patty Becker
At 01:01 PM 12/14/2010, you wrote:
>The direct answer to Nick is that the block
>group data will NOT be posted in American
>Factfinder, and will ONLY be available in Summary File format.
>
>Ed's response was about reasons why the Census chose this differentiation.
>
>Elaine Murakami
>FHWA Office of Planning
>
>
>-----Original Message-----
>From: ctpp-news-bounces(a)chrispy.net on behalf of edc(a)berwyned.com
>Sent: Tue 12/14/2010 12:24 PM
>To: ctpp-news(a)chrispy.net
>Subject: RE: [CTPP] ACS 2005-09 comparisons with 2000 SF3
>
>This is one of those points of speculation and spin. If you ask the CB
>the official line will be that it is so big and contains literally
>mountains of tables that it is impractical to serve up with an online
>search engine. They will tell you that comments on this were asked for in
>the Federal Register and there was not a huge outcry. However, if you
>"put your ear to the ground" you will hear some speculate that it is
>because the tables are so hard to work with due to confidentiality
>suppression and large margins of errors that the CB wanted to keep the
>data from the "novice" user. As one noted user put it, "they are putting
>the data on the top shelf just out of reach of the kids."
>
>What would be of use here is for people who have begun to work with it to
>share their experiences.
>
>Form the CB press release today...
>The U.S Census Bureau is pleased to announce the release of the 2005-2009
>American Community Survey (ACS) 5-year estimates on American FactFinder.
>There you will find tables with social, demographic, housing, and economic
>data for areas down to the census tract level.
>
>You can access the newly-released data on American FactFinder at:
>2005-2009 ACS 5-year data
>http://factfinder.census.gov/servlet/DatasetMainPageServlet?_program=ACS&_s…
>
>
>
>
>
>
> > Does anyone know why the Block Group data is not being released via the
> > AFFâ?Ts standard pull-down menus? I was under the impression that today
> > (12/14) was the release date for this data. I understand that it is
> > available via Summary File, but this is far from user friendly.
> >
> >
> >
> > When will the data be available via the AFFâ?Ts standard access method?
> >
> >
> >
> > Thank you,
> >
> > Nick Lindeman
> >
> >
> >
> > Nicholas Lindeman
> > Economic & Systems Data Analyst
> >
> > Nashville Area MPO
> > 800 2nd Ave. S.
> >
> > P.O. Box 196300
> > Nashville, TN 37219-6300
> > (615) 862-7198
> > lindeman(a)nashvillempo.org
> > http://www.nashvillempo.org <http://www.nashvillempo.org/>
> >
> >
> >
> >
> >
> >
> >
> > From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces@chrispy.net]
> > On Behalf Of Elaine.Murakami(a)dot.gov
> > Sent: Tuesday, December 07, 2010 4:15 PM
> > To: ctpp-news(a)chrispy.net
> > Subject: FW: [CTPP] ACS 2005-09 comparisons with 2000 SF3
> >
> >
> >
> > Correction to my earlier email: 2005-2009 ACS Block Group data WILL be
> > released on December 14.
> >
> >
> >
> > From: brian.mckenzie(a)census.gov [mailto:brian.mckenzie@census.gov]
> >
> > Good Afternoon Mara and Elaine,
> > The summary file data (block group level data) will be available on
> > December 14th. You can use American Factfinder as a portal. You will be
> > able to download summary file data via the FTP website at
> >
> <http://www2.census.gov/acs2009_5yr/summaryfile/
> > <http://www2.census.gov/acs2009_5yr/summaryfile/> >. There will also be a
> > clickable link next to the familiar portion of AFF in which you select the
> > desired ACS year(s) for which you would like data. Hope this helps.
> >
> > Brian McKenzie
> > Analyst, Journey to Work and Migration Statistics Branch
> > U.S. Census Bureau
> > 301-763-6532
> > brian.mckenzie(a)census.gov
> >
> >
> >
> > _______________________________________________
> > ctpp-news mailing list
> > ctpp-news(a)chrispy.net
> > http://www.chrispy.net/mailman/listinfo/ctpp-news
> >
>
>
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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
