Add $2.7 Trillion Dollars To The Debt

For his first annual budget next week, President Obama has banned four accounting gimmicks that President George W. Bush used to make deficit projections look smaller. The price of more honest bookkeeping: A budget that is $2.7 trillion deeper in the red over the next decade than it would otherwise appear, according to administration officials.

Who does their accounting? How do we know this number is "right"?