Very helpful
Alan E. Pisarski
6501 Waterway Drive
Falls Church Va. 22044
703 941-4257
alanpisarski(a)alanpisarski.com
_____
From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces@chrispy.net]
On Behalf Of Graham, Todd
Sent: Monday, October 06, 2008 1:47 PM
To: 'ctpp-news(a)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 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(a)tjcog.org>
Subject: [CTPP] seeking guidance on worker flows from the local employment
dynamics On The Map data
To: <ctpp-news(a)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(a)tjcog.org
www.tjcog.org