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@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:
  1. 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.
  2. 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/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