Yesterday’s Gallup Tracking Poll showed McCain up by an insignificant 2% (46% to 44%). Today showed a 3-point swing in just one day, to Obama up an insignificant 1% (45% to 44%). Today’s release is an average of polls done on Sunday, Monday, and Tuesday.
While it may be just random variation, a 3% jump in a 3-day average in one day suggests that Obama polled about 8-10% better in the Tuesday polling (added today to the 3-day Tracking Poll) than in the Saturday poll (dropped today from the Tracking Poll). That difference should be statistically significant, since both daily polls were done with about 900 respondents.
We will have to wait a few more days to see if this difference is real or a 1-day aberration. After all, they average these polls for a reason.