What is the current state the Presidential race? The answer depends on who you think is likely to vote, a point Mark Blumenthal makes over at Pollster today. And the gap between registered voters and likely voters can be sizable: in the latest ABC News/Washington Post survey, President Obama’s six-point lead among registered voters becomes a single percentage point when shifting to likely voters. Similarly, if we look at the last two polls conducted by CNN, we see that President Obama’s post-convention bump was primarily a change in the composition of likely voters, not in the preferences of registered voters—as the Times’ Nate Silver was quick to point out.
But imagine that you reach a voter on the phone, and she tells you she is unlikely to vote. What is the chance that she still will do so in the end? A working paper by Masa Aida and Todd Rogers reports the answer from three different studies, including one which compares survey responses and actual turnout for more than 10,000 voters in 39 states during the 2008 general election. How people answer a survey question about their vote intention does predict whether they are likely to vote, with 87% of those who say they are almost certain to vote actually doing so. But one striking finding is that 55% of those who say they will not vote still do so in the end. Now, that figure did drop to 29% in New Jersey’s 2009 gubernatorial election—but even 29% is far from zero. So don’t be surprised when you see a lot of “unlikely voters” at the polls in November. Much more is in the paper.