Very helpful
Alan E. Pisarski
703 941-4257
alanpisarski@alanpisarski.com
From:
ctpp-news-bounces@chrispy.net [mailto:ctpp-news-bounces@chrispy.net] On Behalf Of Graham, Todd
Sent: Monday, October 06, 2008
1:47 PM
To: 'ctpp-news@chrispy.net'
Subject: [CTPP] RE: seeking
guidance on worker flows from the local employment dynamics
John,
I got involved with this
6 years ago, when
Census LED works with
state employment agencies (Unemployment Insurance, Labor Statistics, etc.) and
with Federal data sources to data-mine residential
location and worksite of all covered SSNs.
State employment agencies
know where everyone works (* everyone who’s legally employed, that is).
And the Feds know where everyone lives, with linked SSN (again, caveats
to this). This project is the fruit of the CIPSEA Act of 2002 – allows
agents of the Dept of Labor, Census Bureau, other Fed agencies, to share what
would otherwise be “private” or “nonpublic” data.
And the deliverable is a
Census Block-level origin-destination table with a count of commuting workers
(jobs). Very detailed! In fact, so detailed that Census disclosure
gurus determined need to limit the detail provided in certain data elements
– and to smudge or “fuzz” geographic specificity of
employment worksites.
I understand discomfort
with smudging, fuzzing, and simulating. Still, I’d look to this
source for origin-destination pair granularity that future ACS-based CTPP will
be flat-out unable to provide.
In the
future, I can imagine Census LED being combined (thru Iterative Proportional
Fitting) with Census ACS summaries (control totals) and ACS PUMS to produce
synthetic population with detailed residence-to-worksite linkage. But
this is just a dream right now, and not sure it’s a vision that others
share.
-- Todd
Graham
Metropolitan Council Research
651/602-1322
----------------------------------------------------------------------
Date:
Mon, 6 Oct 2008 08:38:49 -0400
From:
"John Hodges-Copple" <johnhc@tjcog.org>
Subject:
[CTPP] seeking guidance on worker flows from the local employment dynamics On
The Map data
To:
<ctpp-news@chrispy.net>
Does
anyone have a short, "plain English" explanation of the
residence-to-workplace flows from this data and how it compares to the old
long-form commuting data from the 2000 and earlier censuses (censi?). I read
"synthesized" data and little red flags go up. Specifically, is
this data based on actual residence and workplace data of real individuals (as
with the Census), or are the residence and workplace locations from different
data sources and the travel between the 2 synthesized in some way, as a travel
demand model would create travel patterns between the 2?
Any
guidance would be appreciated; my brief hunting through the documentation
didn't give me the clear specifics I was hoping.
Thanks,
John
Hodges-Copple, Planning Director
Triangle
J Council of Governments
919-558-9320
johnhc@tjcog.org
www.tjcog.org