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?
While McCain is definitely getting a bounce in the polls, pollsters seem to be--at the same time--increasing the number of Republicans that they poll and decreasing the number of Democrats.
Now weighting polls is standard operating procedure, but making this change, while McCain is getting his convention bounce is amplifying the magnitude of this bounce. What is less than clear is if this is a real effect, or artificial.