As if nervous Democrats didn't have enough to worry about, on the morning of the second presidential debate, USA Today and the Gallup Poll released a new poll of 12 swing states that shows Mitt Romney leading Barack Obama by 4 points among likely voters. The poll shows Mr. Romney with an 8 point lead among men. More surprisingly, according to the poll, Romney is holding Mr. Obama to a 1 point margin among women.
If true, these results would be devastating for the Obama campaign, which is counting on a large margin among women to offset Mr. Romney's strength among men. A 4 point margin in the swing states would mean that if the election were held today, Romney would win the large majority of the electoral votes from these states and that would almost certainly give him more than the 270 overall electoral votes needed to win the election.
But are the results of the USA Today/Gallup swing state poll an accurate snapshot of the state of the presidential race in the swing states today? Based on the results of dozens of polls conducted in these same states over the past few weeks, the answer to this question is almost certainly no.
For its swing state polls this year, Gallup included 12 states expected to be competitive in the presidential election: Colorado, Florida, Iowa, Michigan, Nevada, New Hampshire, New Mexico, North Carolina, Ohio, Pennsylvania, Virginia, and Wisconsin. I compared the results of the new Gallup poll with the latest estimates of the standing of the presidential candidates in these 12 states based on the HuffPost Pollster's poll tracking model. The poll tracking model uses a sophisticated algorithm to combine the results of state and national polls, weighting and adjusting the results of individual polls based on such factors as house effects and sample size. However, I also compared the results of the Gallup swing state poll with the current RealClearPolitics.com averages for these 12 states and the results were almost identical.
Based on the HuffPost Pollster poll tracking model, there was not a single swing state in which Mitt Romney had a lead of 4 or more points over Barack Obama among likely voters. In North Carolina, Romney's best swing state, he was estimated to have a lead of about 3 points. Obama was leading Romney in 9 of these 12 states with an average lead of just under 3 points. When the individual state results were weighted based on state population to make them directly comparable to the Gallup results, Obama had an average lead of just over 2 points. Using the population-weighted RealClearPolitics.com averages, Obama's lead in these 12 states was just over 1 point.
Both the HuffPost Pollster poll tracking model and the RealClearPolitics.com averages are based on the results of dozens of polls involving tens of thousands of interviews with likely voters in the individual swing states while the Gallup swing state poll is based on interviews with a few hundred likely voters spread across all 12 states. It is clear which of these results one ought to have more confidence in.