The head pollster at Gallup said on Fox this AM when asked by Chris Wallace, that they don’t even consider party affiliation; he had a lot of reasons, that there were no national measurements of affiliation, that it went up and down with the rest of polling, that exit polls asking people to identify are , of course, polls themselves, so Gallup never measures it as an independent variable except for “informational purposes” near the end ( I presume of the election cycle, though he could have meant toward the end of the interview.) He did make a lot of enthusiasm though.
Why the disparity in party affiliation polling between Rasmussen and Gallup?
http://www.gallup.com/poll/15370/party-affiliation.aspx
The fellow from Gallup means at the end of the interview. An easy way to reconcile the surge in support for Romney in Gallup to the modest uptick in Raz, is that Raz weights by the lagging average of party affiliation. Therefore, when party affiliation moves in concert with voter preference, Raz will, for a while, stifle the surge.