How Not To Discredit A Poll

HOW NOT TO DISCREDIT A POLL.... The latest New York Times poll found that 72% of Americans support a public health option as part of the larger reform effort. John Hinderaker at Power Line, a prominent conservative blog, pushed back against the results yesterday, arguing that the poll's sample is skewed in Democrats' favor.

Specifically, Hinderaker found that when respondents were asked which candidate they supported in the 2008 presidential election, 48% said Obama and 25% said McCain. Since Obama actually won 53% of the vote, and McCain won 46%, the poll, Hinderaker concludes, "obviously skews left."

As it turns out, though, it's not "obvious" at all. In fact, the Power Line criticism doesn't stand up to scrutiny. Eric Kleefeld noted:

A big problem occurred to me, though, one known to anyone who's read about polling for a long time: The who-you-voted-for question is good for a lot of things -- except for finding out how people actually voted. It's really an indicator of people's willingness to say they voted for the incumbent (regardless of whether they're telling the truth) or to say they voted for the challenger. All this poll really tells us is that some people are eager to say they voted for Obama, and others won't readily admit they voted for McCain.

Exactly. In fact, Slate's Christopher Beam did a good piece on this just a few days ago, explaining in some detail that Americans routinely take some liberties when asked by pollsters who they voted for, and the phenomenon has existed for decades.

What's more, not only did Hinderaker's efforts to cast doubt on the NYT poll come up short, but he'll also have to work harder to get the results he'd like to see. For one thing, even within the NYT poll, 50% of Republicans support a public option. Even if Power Line is convinced there weren't enough McCain voters among the respondents, it doesn't explain the popularity of the public plan. For another, the NYT poll isn't the only one -- an NBC/WSJ poll that showed 76% of Americans believing that it's important to "give people a choice of both a public plan administered by the federal government and a private plan for their health insurance," and a D.C. policy think tank conducted a poll, financed in part by previous opponents of health care reform, which found 83% of Americans favor a public plan.

Nevertheless, arguments like Hinderaker's can have an impact, even if they're easily-discredited. Yesterday, Sen. John Cornyn (R) of Texas cited the bogus Power Line criticism in two national television appearances: "'With all due respect to the New York Times and CBS, this polling sample was skewed,' he told MSNBC's Andrea Mitchell. Similarly, on Fox News Cornyn said, 'I think there's been some particularly good blog coverage like Powerline blog talking how that sample was so skewed as to be meaningless.'"

If recent history is any guide, news outlets will start referring to recent polls on the public option as "controversial" and "possibly skewed," even though reality shows otherwise.