Unlikely Voter

If we look at a series of five polls of the Wisconsin Senate matchup between Senator Russ Feingold, Democrat, and former Governor Tommy Thompson, Republican, we find a broad range of results.

On no news can we really expect the race to move 16 points in one week? Some of these have to be wrong, but will we ever know which?

When I see people, and particularly conservatives, discussing why one poll is better than another, I see the sample pool frequently cited as a reason for favoring one or another. Specifically, some poll watchers insist that any poll not filtered for likely voters, instead of just registered voters or even adults, is not useful in a political context.

The dirty secret is that not all likely voters are created equal. Every pollster has his own secret sauce, and we have to be careful when trusting that kind of filtering. It might not be what we expect.