Could One Pollster Be Right And Every Other One Be Wrong?
He changes the baseline assumption on how much of the electorate is Republican and how much is Democratic. Initially, he used Rasmussen’s real numbers on party identification to re-weight various polls. Rasmussen’s numbers break down to 37.6 percent Republican, 33.3 percent Democrat and 29.2 percent Independent. As of Thursday night, Chambers began using party identification numbers from his own web-based poll.
…Chambers insists he isn’t “changing” or “making up” data. “The only thing I’m doing is weighting.”
But that’s exactly what most pollsters don’t do. “We don’t have any preconceived notions about the party breakdown of a poll before we conduct it. The only things we make any adjustments for are gender, race, and age,” Democratic-leaning Public Policy Polling’s Tom Jensen told TPM in an email. “It makes sense that as support for Obama increases, more people also identify themselves as Democrats. I know conservatives want to think it’s more Democrats in the poll causing Obama to do better, but it’s actually Obama doing better causing more Democrats in the poll.”