The Wall Street Journal published an article comparing Mitt Romney to his father George Romney, who ran for president in 1968, but ignored an important distinction between the two: George Romney released 12 years of tax returns, while Mitt Romney still refuses to release more than the most recent two years.

In its article this morning, the Journal contrasted George Romney's 1968 campaign with Mitt Romney's 2012 campaign, calling George “a guiding force in Mitt Romney's campaign” and “the ghost in Mitt Romney's machine.” While the article laid out several areas in which Mitt Romney's campaign differed from his father's, it ignored one of the most glaring differences.

In 1968, George Romney released tax returns for the previous 12 years, saying at the time “One year could be a fluke, perhaps done for show.” Mitt Romney, however, has consistently refused to release anything but the most recent returns. On September 21, Romney released  his tax information for 2011, making his total disclosure only two years. 

In lieu of releasing his returns, Romney released a summary of the past 20 years' worth of his taxes, along with a note alleging that his average tax rate for that period was 20.2%. But the “average” rate that Romney released was a simple average, which the Tax Policy Center's senior fellow Roberton Williams describes as misleading. In the Washington Post, Williams pointed out that the number released by Romney “can distort the rate you've paid relative to your income”:

“Let's say you have 10 years in which you paid 13 percent in taxes, and 10 years in which you paid 27 percent,” Williams told me. "If you average those rates, you'll get an overall rate of 20 percent. But if the 13 percent years were high income years, and the 27 percent years were low income years, then his total taxes paid as a share of total income over the 20 years would be less, perhaps significantly less, than 20 percent.

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“You can be a person like Romney and have a highly fluctuating income year to year,” Williams said. “Some years Romney's income could be much lower than in other years. When you average just the rates, you can distort the rate you've paid relative to your income over the whole period.”