The word ‘audit’ just means a check to see if processes are followed.  The .gov, just like the military, is big on processes and documentation.  So a minimally competent database analyst or programmer could probably write some back end code and run some cross checks to see if all the process boxes are being checked after reviewing the process documentation.  Then you can have a 4-year argument with CPA’s and lawyers and Congress to decide if the process documentation follows any applicable statutes or publicly accepted methodologies.

You actually have to do a forensic examination to determine if processes are reasonable and/or fraud is occurring.  Some basic ideas would be to run some stats, bin the data and look for extreme values (125 year olds, for example).  Anyone with data analysis background can do these basics, plus a lot more.  

The .gov has had an issue for decades now of old databases, old architecture, old programming languages, and the people that learned Fortran as youngsters are in nursing homes now, so you have to have someone adept to do the archeology on the technology and get answers that should be easy to get except for decrepit IT.  My cousin is helping Baltimore do this - one of the things they apparently forgot is how to actually calculate the property taxes, the old 1970’s mainframe just spits out numbers (on some sort of tape cassette, no less) and so you can’t just port over the software - it all has to be rewritten and the process documents are lost or inadequate and the people who wrote and understood them are in a cemetery or nursing home, but the game of hot potato is going to come to an end soon when they run out of easy ways to replace things like vacuum tubes and such.