attorney jeff schnepper, an expert on u.s. tax policy, breaks it down in simple terms. >> so, if you're living in beverly hills and you show an income of $20,000, there may be an issue. it's gonna click the computer. if you're living in the ghetto and you're showing a $30,000 charitable contribution, it's gonna click the computers. >> quick: still, most cheaters are not caught. but before you think scamming the irs sounds like a good deal, think about this. >> if people paid what they owed, we'd fund social security, we wouldn't have a deficit. even states like california, in the long run, would be in the black instead of the red. >> quick: it's called the tax gap -- $300 billion a year in uncollected taxes -- the difference between what is actually reported and paid to the irs and what the agency says should be reported and paid. nina olson is the national taxpayers advocate. her government office helps taxpayers and proposes irs reforms to congress. >> essentially, the tax gap translates into $2,200 that each taxpayer pays f