Over at taxpayer supported NPR, its "Morning Edition" co-host Renee Montagne said in January: "Yesterday, Romney did let slip a provocative tax detail. He acknowledged he's probably paying an effective tax rate of around 15 percent. And that's well below the rate that many middle-class families pay (emphasis added)."

One problem. It isn't true -- not even close.

First, as with the purchase of new car, almost nobody pays sticker price. To make Romney's "low" effective tax rate look bad, some news media irresponsibly compare his rate to that of a middle-class taxpayer's top marginal rate.

Just how misleading?

Assume Mr. Auto Mechanic is married, with two children. After offsetting income with exemptions, deductions for things like mortgage interest and assorted tax credits, Mr. Mechanic's effective federal income tax rate -- the percentage of income actually paid in taxes -- is much less than Romney's rate.

The liberal Tax Policy Center reports that 91.4 percent of individual taxpayers with adjusted gross incomes (AGI) between $50,000 and $100,000 pay less than 15 percent in taxes. And 43.9 percent of the $50,000-$100,000 AGI taxpayers pay an effective rate between 5 and 9.99 percent, while 4.6 percent of this group pay no federal income tax at all.