The Gallup national tracking poll now shows a very strong lead for Mitt Romney. As of Friday, he was ahead by six points among likely voters, having led by seven points on Thursday.

However, the poll’s 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 now show a very slight lead for President Obama on average, while state polls continue to indicate a narrow advantage for the president in tipping-point states like Ohio. The FiveThirtyEight forecast has Mr. Obama as a modest favorite in the election largely on the basis of the state polls.

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