"Overseeing the overseers" is one way to describe what the office of the inspector general (IG) does for any US government agency.
At the Department of Transportation (DOT), for example, the IG investigates a whole range of activities, from building contractors who use faulty materials to airlines that cut costs on repairs and maintenance to DOT staff who steal office equipment.
As watchdog for the 12 DOT agencies, including the Federal Aviation Administration and the Federal Highway Administration, the IG often ...