John,
I got involved with
this 6 years ago, when Minnesota was the first
pilot state. Maybe I can do plain
English…
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
PO
Box
12276
Research Triangle
Park, NC 27709
919-558-9320
johnhc@tjcog.org
www.tjcog.org
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