Re: [CTPP] Re: Geographic coverage, C2SS & ACS - ctpp-news

8 Nov 2001

Again, please feel free to post this to the list serve if you wish.

My clear understanding is that "small area" means tract.  I don't think 
anyone thinks the 60 month data will be good enough for block groups.

If TAZs are tract equivalent, then the data should be as good as for 
tracts.  For heavy attractor TAZs which are split below tract level, the 
transportation community has to negotiate with the bureau for a special tab 
to deliver all TAZs.  The data should support the tab 
adequately,  Meanwhile, of course, someone is going to have to be 
responsible (MPO by MPO and state by state) for keeping the geocoding file 
up to date!

No one knows whether these 60 month data are going to "feel right."  Only 
time will tell.  But in any event the CTPP users will have data equivalent 
to that for all users who use tracts.  Meanwhile, we still have all these 
hurdles in Congress, etc. etc.

The C2Ss is separate from the ACS.  There is no way that the number of 
cases will allow for TAZ level reporting, even if the 2000 and 2001 surveys 
are combined.  Perhaps we can get combined data at the 100K level out of 
them next year.  I would suggest, however, that the CTPP community keep a 
good handle on how the coding is proceeding for the C2SS--are they doing a 
good job of it?  The ACS will be like the C2SS in this regard and if there 
are problems, it's important to be aware of them.

Patty Becker

At 02:05 PM 11/08/2001 -0600, ed christopher wrote:
...
 Elizabeth and Ed-- (note, I am not posting this to the
listserv, but Ed can
choose to post it if he wishes)

At the current time, I believe that with the current plans for sampling for
the ACS, it would take 5 years of accumulated data (60 months) for the
Census Bureau to release small area data. However, if the sampling rate
decreases to any large extent, it is not clear what would happen to small
area data.   To clarify Ed's earlier remarks, we do not know if "small
area"
means census tract, or block group level geography.  We are very concerned
about whether and how the transportation community will be able to generate
an "equivalent" to a CTPP file from the ACS, and if reporting by TAZ will be
possible or allowed.

Elaine Murakami
Federal Highway Administration

Keith Miller wrote:

 > According to the Census Bureau
 > (http://www.census.gov/Press-Release/www/2001/ntc102901.html):
 >
 > "By 2004, the American Community Survey ... will produce estimates for
 > geographic areas and population groups of 65,000 or more, and by 2008, for
 > even the smallest areas and population groups in the country."
 >
 > Just what "the smallest areas and populations groups" means is
anyone's
 > guess, but it was my understanding that they're targeting the block-group
 > level. But as Ed pointed out, this all depends on congress and funding...
 >
 > Also to address one point that Elizabeth asked in her original question,
 > "will the C2SS and the ACS provide transportation data at this fine a level
 > [block group]?" It is my understanding that the C2SS (Census 2000
 > Supplementary Survey) data will not be available for anything smaller than
 > counties or cities with more than 250,000 residents. The sample size of the
 > C2SS was not sufficient to support anything smaller than this. For the ACS,
 > see above.
 >
 > ------------------------------------------------------------------------
 > Keith Miller
 > Principal Planner: GIS and Modeling
 > North Jersey Transportation Planning Authority, Inc.
 > One Newark Center, 17th floor
 > Newark, NJ 07102
 > 973-639-8444
 > kmiller(a)njtpa.org
 >
 > -----Original Message-----
 > From: owner-ctpp-news(a)chrispy.net [mailto:owner-ctpp-news@chrispy.net]On
 > Behalf Of ed christopher
 > Sent: Wednesday, November 07, 2001 4:43 PM
 > To: Elizabeth Hartmann
 > Cc: elaine (fta) murakami; ctpp-news maillist
 > Subject: [CTPP] Re: Geographic coverage, C2SS & ACS 
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Patricia C. (Patty) Becker             248/354-6520
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