25 Aug
2021
25 Aug
'21
2:30 p.m.
Todd:
The pro-tips on building PUMAs (discourage splitting counties; encourage consistency with
city boundaries) make great sense.
(I’ve had a lot of fun using the POWPUMA data from PUMS. In California we have 58 counties
and 41 POWPUMAs. Good for trying to analyze county-to-county commute patterns over the
years.)
QUESTION: When will the 2020 Census Summary File #1 be released? I can’t find the
information on the Census Bureau’s website. My hunch is that it will be about four months
after the PL 94-171 data is released, perhaps by December 2021???
The SF1 (STF1A to old-timers) will have the detailed “short form” tabulations including:
households by household size, detailed age cohort tables; householder tables; detailed
hispanic groups; detailed asian groups; owner/renter tenure; etc.
Chuck
On Aug 23, 2021, at 1:01 PM, Graham, Todd
<todd.graham(a)metc.state.mn.us> wrote:
Hi Chuck—
Thanks for the heads-up. Yes, that is the way to think of PUMAs = as “super-districts”
or sub-state regions.
Here are my “pro-tips” learned in PUMA drawing 10 years ago:
Do not group together fractional pieces of counties when you could keep a county whole,
or when you could group multiple whole counties together in a PUMA.
When splitting counties into multiple PUMAs, try to arrange for the split lines to be
stable city/town boundaries. This means you’re looking to create PUMAs where city/town
boundaries are aligned with Tract boundaries. (Because Census Geog Dept will require that
tracts be the basic units of PUMA assembly.)
The reason I emphasize parsimony with counties in point #1 is: The PUMAs you draw will
enable or limit the detail of MIGPUMAs as well. (MIGPUMA= Migration origination geographic
units) Census Bureau will create MIGPUMAs as the least common denominator grouping of
counties that is entirely coincident with a group of PUMAs. So don’t split counties
unnecessarily.
The reason I emphasize city/town boundaries in point #2 -- even though Census Geog
discusses tracts as the basic units – is this: The PUMAs you draw will enable or limit the
detail of POWPUMAs. (POWPUMAs = Place of Work geographic units) Census Bureau will create
POWPUMAs as the least common denominator grouping of counties + places that is entirely
coincident with a group of PUMAs.
Stated differently: Census looks for combinations of county + place to uniquely nest
within a POWPUMA.
Why is this the standard for POWPUMAs? It’s because of the questions asked on ACS: ACS
asks specifically for the county + place of one’s work location. The PUMA final criteria
document
https://www.census.gov/programs-surveys/geography/guidance/geo-areas/pumas/…
<https://www.census.gov/programs-surveys/geography/guidance/geo-areas/pumas/2020pumas.html>
does say all this, but you’d have to read all the way to the last 3 pages of that
document to find it.
That’s all my advice. Good luck!
--Todd Graham