This may be of interest to users of the 2012-2016 CTPP.
The Part 3 journey-to-work “flow” tables DO INCLUDE the Census Bureau’s (primary)
allocation of workers to county-of-work, and place-of-work (and by extension,
POWPUMA-of-work, since all POWPUMAs are single counties or groups of counties). So, the
user can readily match the CTPP commuter flows with “standard” American Community Survey
2012-16 tables (retrieved via
data.census.gov <http://data.census.gov/> or the
r-package “tidycensus”).
On the other hand, the Part 3 CTPP tables DO NOT INCLUDE the “extended” allocation of
workers, that is, allocated (imputed) to the tract, TAZ or TAD of workplace. I really
can’t point to the documentation where this is made any clearer.
So, I examined the county-to-county total commuters (CTPP Table A302301) for 9 states,
plus the Northern California Mega-Region (24 counties). I then compared the
county-to-county total commuters to the tract-to-tract summary level, summed to
county-to-county level.
The basic finding is that the tract-to-tract total commuter file is missing about 20
percent of the workers. They were *not* allocated (imputed) to the tract-of-work level. (I
can think of dozens of strategies to handle this predicament.)
Here’s a table summarizing these results.
I’ve also uploaded my R-scripts for three states: Idaho, Alaska, and Delaware, to my
GIST/Github:https://gist.github.com/chuckpurvis
<https://gist.github.com/chuckpurvis>
Can somebody double-check my work? Check it using datafiles downloaded from the Beyond
2020 CTPP and/or datafiles pulled using the r-package CTPPr. Sometimes CTPPr doesn’t work
for VERY large data pulls, or even smaller areas (like Alaska state for whatever reason.)
Hopefully this is worth discussing.
cheers and Happy Pi Day!
Chuck