"I've talked to a lot of investigators on this and in one report, for example, the inspector general found that half a billion dollars of claims for new home buyer tax credit could be ineligible," Grabell said.
Then there is also the issue of questionable projects and whether they really deserve to receive the stimulus money.
"We've gone through records that said they spent money on lion and tiger dens at the National Zoo in D.C., stopped modified funding for fish sperm, resetting headstones at cemeteries, cleaning bird droppings," said Grabell.
Obama administration officials say that it is easy to overstate mishandling in stimulus projects. The money, officials told ABC News, is unfolded with great transparency. It doesn't mean there are mistakes but when they are discovered, they are fixed.
"This program has run cleanly, smoothly and transparently," Obama said today while explaining the challenges of implementing a large bill.
The administration is also working to convince Americans that the stimulus is indeed helping them, including their own supporters. On Tuesday evening, former Obama for America campaign manager David Plouffe sent an e-mail to supporters of what's now called Organizing for America, asking them if they're "wondering what ... President Obama's stimulus bill -- has accomplished?"
If so, he tells them to look a chart showing how job losses have steadily become less horrible.
Plouffe says "while this anniversary isn't a cause for celebration, there is reason to be optimistic. This chart makes it clear: We're on the road to recovery."