http://www.weeklystandard.com/blogs/morning-jay-are-polls-tilted-toward-obama_653067.html
Republicans, by and large, are frustrated with recent polls of the presidential election because they think Democrats are being oversampled. Many pollsters respond by saying that “weighting” the polls for partisan identification creates its own problems and might end up skewing the polls in the wrong direction.
I am not in favor of partisan weighting, per se, although some polls like the Rasmussen poll do it in a sensible and nuanced way. So, I think the pollsters are offering a false choice between weighting and not weighting.
Furthermore, a lack of weighting creates its own problems, which many pollsters often fail to acknowledge. Specifically, many polls have, in my judgment, overestimated the Democrats’ standing right now. I base this conclusion not on a secret, black box statistical methodology or some crystal ball, but rather on a read of American electoral history going back to 1972. If I am right, then some of the polls are giving a false sense of the true state of the race, and will likely correct themselves at some point or another.
One important “tell” in my opinion, is this president’s continued weak position with independent voters, who remain the true swing vote.
Obama’s average overall margin over Romney in these same polls is roughly 4 percent. Bottom line: You do not get a four-point lead overall with a tie among independents, unless you are squeezing substantially more votes out of your base than your opponent is. And more generally, you are not “winning” an election in any meaningful sense of the word when 3/5ths of unaffiliated voters are either undecided or against you.
So, I see two ways the polls are tilted in favor of the president.