08/05/2009 04:49 pm ET | Updated May 25, 2011

On Rasmussen's Index and Intensity of Opinion

Last week, TPM's Eric Kleefeld examined the "Presidential Approval Index" reported daily by Rasmussen Reports. Rasmussen calculates the index by subtracting the percentage that "strongly disapprove" of the job Barack Obama is doing as president from the percentage that "strongly approves." Since the index has been a negative number since early July, it should come as little surprise that conservative web sites have frequently reproduced the chart of the index featured in Rasmussen's daily analysis.

Kleefeld asked me and a few others about the Rasmussen index:

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."

I stand by the gist of that comment but, to borrow an Obama-inspired euphemism, I'll concede that I might have "better calibrated" my use of the word "report." Yes, Rasmussen reports the total percentages of those that approve and disapprove on their website. We dutifully enter those percentages into our chart every day, and anyone who looks for the percentages for total approval and disapproval can find them on

My point was more about the emphasis that Rasmussen Reports gives the "index." Their daily analysis, for example, typically reports the latest value of the index in the first paragraph but buries reference to the total approval number at the end, often following results from other questions. During July, Rasmussen's Twitter updates reported on the latest Index numbers at least 20 times (including the percentages that strongly approve and strongly disapprove") , but never once mentioned the total approval percentages.

Since Kleefeld's piece appeared, they have started citing the total approval number in their twitter feed and now include a total approval chart in the daily analysis. So let's at least give Rasmussen credit for responding to criticism.

And let's move on to the substance. Rasmussen told Kleefeld that he began breaking out strong approval and disapproval numbers partly because of his theory that intensity of opinion would matter more in a mid-term election cycle like 2009-2010:

"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."

That hypothesis is reasonable. The ongoing debate those who choose to attend town-hall meetings is about whether they reflect a real wave of intense anger at the Obama administration, and Rasmussen is not the only pollster to see Obama's strong disapproval rating rise. Just yesterday, Republican pollster Glen Bolger blogged about the signs of a "tide of intensity" he sees "moving solidly against Barack Obama" in the recent survey that he and Democrat Stan Greenberg conducted for NPR.

To put this issue into some perspective, I gathered all of the recent surveys that probed the intensity of feeling regarding President Obama's job rating. The table below includes results from five pollsters based on surveys fielded in the second half of July (I averaged the results for Rasmussen over this period and included both of the Economist/YouGov internet panel surveys).


The table shows quite a lot of variation in the "strong" categories. Strong approval varies from a low of 25% to a high of 40%, while strong disapproval varies from 28% to 39%. If we calculate Rasmussen's index, it ranges from a low of -9 (Rasmussen) to +10 (ABC/Washington Post). Why the variation? Differences in the population interviewed appear to explain some of it -- with samples of "likely voters" yielding bigger "strong disapproval" percentages -- but differences in survey mode (whether it interviewed by telephone with live interviewers, by telephone with an automated method or over the internet) and question format may have been important too. The point is that the "true numbers" regarding intense approval and disapproval are lost in a fog of methodology.

But regardless of which poll you believe, all have shown a similar trend in strong approve and disapprove numbers since the spring. Four of the five pollsters also conducted surveys in March or April, and all of these showed single-digit declines in Obama's strong approval rating and similar single-digit increases in strong disapproval.


If I average results for these four pollsters in both time periods (giving each pollster equal weight), we go from an index of +12 in March/April (37% strong approve, 25% strong disapprove) to zero now (31% strong approve, 31% strong disapprove).

So what do these numbers tell us about the state of public opinion regarding the Obama administration? Intensity of approval is moving in the same basic direction as overall approval. Obama's ratings are trending downward either way. As Bolger points out, "this is NOT a case where voters have been moving only in the middle -- from somewhat approve to somewhat disapprove."

Also, and perhaps more important, as of late July there were about about as many Americans who strongly approved of Obama's performance as strongly disapproved. In other words, there are about as many Americans thrilled with his performance as angry about it, although the balance may tip slightly toward the negative among habitual voters. Whether you see that result as implying a jar half empty or half full for Obama probably depends on whether you are one of the thrilled or one of the angry.   

PS: All of the above concerns Obama's overall approval. Intensity of opinion on health care reform is probably different. Note for example that while today's CNN survey shows more in favor (50%) than opposed (45%) to "Barack Obama's plan to reform health care" (the most positive result by far of the last few weeks), the numbers look different when CNN presses for intensity of opinion: Twenty three percent (23%) are strongly in favor, but far more (33%) are strongly opposed.