Source:
The Source field can contain any 8 letters or #'s.  The sample 
data has Sources like OPM (for OFFICE OF PERSONNEL MGMT, US GOVT), 
or FAA for Federal Aviation Administration.

Your small company might want to get it's sources from different
departments or regions of your corporation. Or if you are in a 
large H.R. Dept & you are working on a project w. several co-
workers all inputting KSAs you might want to use USER initials.