Skidmore's estimate, based on a careful reading of publically available documents on government spending under three administrations between 1998 and 2015, was calculated after intense digging by the professor and his team, including poring over government websites and making repeated requests (often unanswered) to government officials for more information.
According to Skidmore, his investigators' persistence led the Office of Inspector General to temporarily disable website links to files showing possible misappropriations and waste. Unfortunately for the agency, his team had downloaded and safely stored the documents before that happened.
Skidmore told USAWatchdog.com that his findings remain incomplete, being only what he and his team have managed to find by looking through Office of Inspector General reports back to 1998. At the same time, he said, the "biggest chunk" of unaccountable spending came from the US Army, with $11.5 trillion in possible misappropriations found over a thirteen year period.
The economist is now lobbying lawmakers to further investigate the "gargantuan nature" of this undocumented spending, which he stressed "should be of great concern to all taxpayers."