I am comparing CTPP 2000 county-to-county flows vs. travel demand model for a mid-sized region. There are a number of complicating issues, including:

Census work trip may not be made every day

Census work tour may be coded as other than home-based-work (HBW) trips in trip-based model

Census only records one commute for workers with more than one job

In trying to massage the data to be as consistent as possible, I also reviewed ES-202 and BEA county employment data. The BEA totals including proprietors are very high, but the BEA wage and salary totals are reasonably consistent with ES-202 data, i.e. consistently higher as they include non-covered employment including government.

However, the CTPP flow data are not particularly consistent with ES-202 and BEA, i.e. some counties appear to attract more commuters than indicated by ES-202 and BEA, and other counties attract less than ES-202 and BEA (after adjusting so the totals are the same).

Have others observed similar discrepancies? Does anyone have advice for reconciling these datasets?

Norm Marshall