The Rasmussen “Presidential Approval Index”: Is This Newer Measurement Worth Anything?


Some commentators on the right have been pointing to an interesting number that has been coming from the Rasmussen daily tracking poll, which Rasmussen bills as the “Presidential Approval Index,” which Scott Rasmussen only began bringing out in late 2008. The key questions then are: What is this number, and is it a valid measurement of real popularity? In an interview today with TPM, Rasmussen defended the index’s validity against some harsh criticism, saying that intensity of opinion — the true figure measured by his index — does indeed matter.

The thing to remember is that this is not simply subtracting all the respondents who disapprove of President Obama from the people who approve. Instead, Rasmussen takes the numbers who strongly approve or disapprove, and then performs this math. As of today, that index number is -10, compared to an overall rating of +1 in Rasmussen’s daily tracker.

It would seem at first glance that this number can skew negative — that is, the people who disapprove of a president are inherently more likely to feel strongly about it, compared to a certain level of lukewarm support for a president. For example, the 2004 exit poll put George W. Bush’s strong approval at 33%, to strong disapproval of 34%. But his overall approval was 53% to disapproval at 46%, and he was re-elected 51%-48%.

I asked three prominent polling experts about this, and they all lambasted it.Mark Blumenthal of said he didn’t know of anyone who had previously given this as a prominent “index.” “If Obama now has more strong detractors than strong supporters, that is politically meaningful (though contrary to the results of the recent ABC/Washington Post polls, to pick one example),” said Blumenthal. “But to report only those who strongly approve or strongly disapprove of Obama while neglecting mention of the aggregate numbers strikes me as more political spin than analysis.”

Charles Franklin of, who is also my former poli-sci professor, said that it “seems misguided” to write off the moderate approvers and disapprovers. And Prof. Alan Abramowitz of Emory University was quite tough on it: “In my opinion, it makes no sense. It assumes that there’s no difference between those who just approve and disapprove, that the only opinions that count are strong approval and disapproval, but there’ s no evidence to support that claim.”

For his part, Scott Rasmussen defended the index to me. He said he began breaking out the strong approval-disapproval numbers late in 2008, originally for the simple purpose of differentiating himself from Gallup after they got in on the daily tracking gig that had previously been his sole domain. And while he agrees that overall approval will be by far the more important number in 2012, he also thinks that for now the intensity of feeling can have a serious impact on policy discussion and political outcomes.

Rasmussen has a working hypothesis that these numbers could be an important indicator in the lower-turnout midterm elections of 2010, when intensity of feeling can genuinely matter. “I know the intensity by the time we get to 2012 won’t matter as much as the overall number. What I don’t know, and what we’re unsure of, is what it does in 2010,” said Rasmussen. “Clearly, if the President’s numbers are down from where they are now, whether you mean overall or the index, it’s going to be more difficult for Democrats to do well in the midterms. And I don’t know, but I suspect, that if the intensity gap is strong it will hurt them. It definitely hurt the Republicans in 2006.”

For now, Rasmussen said the usefulness of the strong approval-disapproval index could become more apparent over the coming recess. Members of Congress will go home and hear a lot from constituents who are heavily in favor of Obama’s proposals, or heavily against them. “They’re probably not gonna hear from people in August who are kind of lukewarm,” he said. “Now I’m not saying whether that’s a healthy dynamic, but I’m saying people who are more passionate get heard more.”

Above all, Rasmussen rejects any suggestion that this is about political spin.

“The political thing I care about is if Barack Obama, if we have him leading by six points before Election Day last year, I want him to win by six points, because I want our polls to be accurate,” said Rasmussen. And for the record, Rasmussen’s final polls had Obama ahead 52%-46%, which was nearly identical to Obama’s final margin of 53%-46%, and made him one of the most accurate pollsters out there. So don’t count him out.