Poll Tracker

Well, we're scratching our heads around here. Two polls, both conducted by Gallup, both over the weekend, were released today:

The daily tracking poll, as we reported just a few hours ago, has Barack Obama leading John McCain 48 to 40 percent.

A USA TODAY/Gallup poll released today shows McCain leading Obama, 49 to 45 percent.

Why the difference? The USA Today version surveyed "likely" voters, while the daily tracking poll surveys registered voters. But then again, when the USA Today/Gallup pollsters examined registered voters, Obama led McCain, but by a smaller margin than the daily tracking poll: 47 to 44 percent.

According to USA Today, Gallup editor Frank Newport "says not to read too much into [the differences between the polls]. 'Statistical noise' may be largely to blame."

The margin of error on the daily tracking poll is +/- 2 points and on the USA Today/Gallup poll, it is +/- 4 points.