...The Gallup national tracking poll now shows a very strong lead for Mitt Romney. As of Wednesday, he was ahead by six points among likely voters. Mr. Romney’s advantage grew further, to seven points, when Gallup updated its numbers on Thursday afternoon.

The Gallup poll is accounted for in the forecast model, along with all other state and national surveys.

However, its results are deeply inconsistent with the results that other polling firms are showing in the presidential race, and the Gallup poll has a history of performing very poorly when that is the case.

Other national polls show a race that is roughly tied on average, while state polls continue to indicate a narrow advantage of about two points for President Obama in tipping-point states like Ohio. The forecast has Mr. Obama as a narrow favorite in the election largely on the basis of the state polls...

http://fivethirtyeight.blogs.nytimes.com/