Undecideds and Persuadables

Here are two more articles relevant to my recent post regarding undecideds. (See here and here.)   According to the AP/Yahoo poll, almost one in ten voters remain undecided – a slightly higher number than what many of the other surveys are reporting.  As the second article indicates, and as I alluded to in my earlier post, the difference is due in part to the question wording that pollsters use when asking respondents for whom they are likely to vote.  As David Moore points out in the other article cited above, pollsters routinely push undecideds to make a choice.  They also tend not to highlight in their stories the number of respondents who say they might change their mind. Why does this matter?  Keep in mind that pollsters ask people who they would vote for if the election was held today – not who they think they will vote for on Nov. 4, the actual election day.  In other words, there is room for voters who say they are leaning toward someone to change their mind even this late in the process.  Consider that the 2004 exit poll found 9 percent of voters saying they had made up their minds in the three days before the election.  In short, looking only at undecideds in any given poll may understate the number of persuadables remaining in the electorate.  For example, the most recent ABC poll suggests that there are only 2% undecideds remaining. But in the fine print of the poll, you find an additional 3% who say there is a “good” chance they will change their mind.  Among McCain supporters, 4% say they there is a “good” chance they might change their mind, but only 1% of Obama supporters say as much.  In the CBS poll, fully 7% of Obama supporters and 9% of McCain supporters say their minds are not made up.  In the Fox poll, 17% of Obama and 22% of McCain supporters indicate that they support their candidate only “somewhat.”  None of these voters are considered “undecided”, however.   But it suggests that there may be more room for movement in support for both candidates than the top-line survey results suggests.


  1. How do these polls deal with early voting? If the numbers of early voters are as high as reports say, the idea that 10% of voters might change their minds drops significantly – you can’t change your mind once you vote!

  2. Jason – Yes, you are right. The overall number of persuadable voters declines as early voting takes place. In the surveys, pollsters are asking voters if they have voted already, and obviously only asking those who haven’t voted yet how strong their support is. But your point is well taken – 10% of a shrinking pie means less persuadable voters. Note that this is more significant in some states that are showing a large number of early voters (like Nevada). Most of our discussion is in reference to the national tracking polls. At this point, early voting is about 18% of the total turnout in voters for 2004, so assuming equal turnout (and my guess is it will go up this year), the pool of “persuadables” (assuming a 10% rate) is already down 1.8% overall. Don’t know if I’d call that significant – but it is less!

  3. Matt, you have indicated that you thought that Rasmussen and Gallup were the most reliable polls. As of 9 PM Saturday, Rasmussen has the National vote Obama + 5 and Gallup, both Traditional and Expanded at Obama +10. Can you suggest and explanation for this disparity?

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