Robert S. McIntyre, the tireless crusader for higher taxes, had a letter in Saturday’s Washington Post under the title “Fuzzy Math.” Usually McIntyre is directing his ire at the “fuzzy math” of supply-siders and other fiscal conservatives, such as this pdf about Senate Republicans. This time, however, he wrote in to point out an error in the Post’s political data. But was it an error? Here’s McIntyre’s letter:

Fuzzy Math

On Jan. 4, reporting the results of the Iowa caucuses, you said, “Sixty percent of Republican caucusgoers described themselves as evangelicals, according to entrance polls. Those voters went for Huckabee over Romney by more than 2 to 1.” [That article here.] Meanwhile, you also reported that Mike Huckabee received 34 percent of the total GOP vote. This seems impossible.

Even if Huckabee didn’t get a single non-evangelical vote, his two-thirds-plus share of 60 percent of the voters would give him more than 40 percent of the total vote.

Can you explain this?

– Robert S. McIntyre

McIntyre seems to be befuddled by a simple conceptual error. He’s assuming that Huckabee and Romney were the only two candidates, in which case two-thirds of 60 percent of the voters would indeed be 40 percent of the total vote. But in fact, Huckabee and Romney together got only 60 percent of the total vote. So let’s sort through the numbers. The entrance poll surveyed 1600 Republican voters. Of those, we’re told that 60 percent, or 960, were evangelicals. As this Los Angeles Times graphic of the entrance polls shows, Huckabee beat Romney 46–19 among those voters, which suggests he got about 442 evangelical votes among those polled. (And about 35 percent of evangelical voters voted for someone other than Huckabee or Romney.) That’s about 28 percent of the 1600 total voters. Huckabee got only 14 percent of the non-evangelical Republicans polled, or about 90 people. Add the 90 to the 442, and you get 532, or 33.25 percent of the voters surveyed. Which is pretty close to the 34.4 percent that Huckabee got in the actual caucuses.

McIntyre’s error should have been obvious to the Post’s editors. I don’t know why newspapers should publish letters to the editor that contain obvious errors. Would they publish a letter that said “You misspelled Reagan; it should be Raegan”? I doubt it.

Of course, what’s more interesting is that this simple conceptual error about elementary arithmetic comes from a leading “liberal” expert on tax policy, quoted regularly in major newspapers about the interpretation of complex income tax data. Let’s hope he understands those intricate and abstruse data better than he does simple political polls.