Shifts in American political geography (“realignments”), which I wrote about on Thursday, can be viewed at a glance using the following diagr...
Who are these likely voters, anyway?
After Labor Day, most pollsters start to apply “likely voter screens,” in which they attempt to identify respondents who are not just registered to vote, but who will actually schlep to the polls (or vote by mail) in the election. Many of you have asked what is in these screens, and whether to be suspicious of the methods.
My general position is that because of the Wisdom-of-Crowds-of-Pollsters principle, I don’t think it’s worth delving into. That wisdom works very well in on-year elections such as 2004 and 2008, as you can see by exploring the left sidebar. It works a tiny bit less well in off-year elections such as 2010, when media saturation is lower and voter motivation is harder to measure. My view is that it is fully effective to take the likely-voter numbers at face value and calculate medians.
However, I recognize that you want more. Rather than re-invent the wheel, I turn to some classic essays by former polling professional Mark Blumenthal, now of Pollster.com. In 2004 as the Mystery Pollster, he wrote a series of seven essays that cover most of what there is to say. In 2008 he wrote another good essay.
(The advent of wireless phones does not really change anything except for the price of doing a poll. If you have any comment along those lines, a better place is yesterday’s essay by Ed Freeland.)
I do not recommend reading anyone’s commentary from this year on the subject of likely voters. Most writers are trying to argue away Obama’s lead. This is a case of motivated reasoning. I did this with John Kerry’s numbers in 2004, to my regret. What I wrote then is useful as an object lesson in what not to do. It is better to rise above the heat of battle.