How is it possible for McCain to lead in polls when Dems are significantly out-registering Repubs?

[carpe diem]

Answer: it's not without some 'help' from the pollsters

Great article from Seth Colter Walls at Huffpost:


http://www.huffingtonpost.com/2008/09/09/poll-madness-mccain-takes_n_125158.html


Poll Madness: McCain Takes Lead Even As Democrats Out-Register Republicans?

This week's mainstream coverage of the presidential horse-race has been dominated by a series of polls showing the McCain-Palin ticket with its first stable lead over Obama and Biden. Gallup's tracking poll, USA Today and CBS News all show the Republicans with some kind of lead over the Democratic ticket. But, interestingly, all three polls were also conducted using a higher sampling of Republican voters than in July, thus raising a question of methodology.

In a year in which Democrats have a lead of 11 million registered-voters over Republicans, and have been adding to that advantage through a robust field operation, are pollsters over-sampling Republicans?

Despite a raft of advantages in the electorate for Democrats, in September's first Gallup Tracking poll, an equal number of Republicans and Democrats were surveyed (including "leaners") from Sept. 3-5, compared to a 10-point Democratic identification advantage two weeks ago. That partisan makeup of the polling pool resulted in a 5-point lead for McCain in Sept. 5 tracking poll. Meanwhile, the new CBS poll features a 6-point swing in partisan composition toward Republicans, which plays some role in the poll's two-point lead for McCain. Finally, the latest USA Today poll, which claims a four-point edge for McCain, was arrived at after a 10-point swing in partisan makeup toward GOP respondents.

Some polling experts say the changing state of party affiliation in the field is slow to be reflected in polls themselves. Democratic pollster Anna Greenberg told the Huffington Post that "when it comes to registration and turnout, the polls often do a very bad job of taking those into account," because newly registered voters aren't in the voter files used by firms that survey public opinion. "You could make the argument they are under-representing new registrants," she said, which would mean that the Democrats new edge would not be taken into account.

[tridim]

1. Look about 15 posts below yours. They're oversampling Repukes.

[WCGreen]

2. They don't include newly registered voters in the sample...

They tend toward Likely Voters which, in most cases, means you have voted in a Congressional Election as well as a Presidential Election.