One of the coolest things about FlatMerge is that it tells you types and lengths of your data. We're relying heavily on this feature as we build in dynamic OData output (coming soon!). So, browsing around data.gov, we found some interesting raw data about Congressional campaign expenditures https://explore.data.gov/Elections/2009-2010-Candidate-Summary-File/38zs-22s9
Loading this data into FlatMerge (http://flatmerge.com/Data/Details/77e6b770-8ef6-4658-912a-a771d159f270) shows some interesting things...
The description of the data on data.gov says that ZIP Code (can_zip) is 5 digits.
FlatMerge found some ZIP codes to be 9 digits... is this ZIP+4?
Also, it seems strange that the Candidate Incumbent Challenger Open Seat (can_inc_cha_ope_sea) field indicates that it is a 10 character field, but has an explanation for some letter abbreviations.
Turns out, the explanation of the abbreviated data is not needed, because the data contains the full text.
So, the documentation does not exactly match what's truly in the data.