07/28/2008 04:55 pm ET Updated May 25, 2011

"Statistical Dead Heat?" Depends on Which Statistics You Use

"We have a race that by every measure of every poll is a statistical dead heat. McCain's not supposed to be in this thing, and Obama's supposed to be blowing everybody away and it just isn't happening, at least to this point." Lou Dobbs (July 17th, Lou Dobbs Tonight)

If you have paid any attention to the news in the past month, you have had a hard time avoiding some journalist or pundit noting that the presidential race is currently a "statistical dead heat" or "essentially tied." The news media, of course, love to cover the horserace aspects of the campaign, particularly in a way that emphasizes how close the election is. But when you step back and gain a little perspective on the big picture, you realize that this race isn't quite the dead heat that it is made to be.

The news media are often a bit myopic in their view of the contest, extrapolating too much from the most recent poll (or even the most recent "surprising" poll). Last week, Fox News released a national survey that showed Obama holding a 41-40% lead, well within the margin of error for the survey. Commentators were quick to emphasize this result and note that the candidates were essentially running neck-and-neck or that the race may even be tied. No doubt there will be a lot of commotion over the latest Gallup/USA Today survey showing McCain ahead (though also within the margin of error) among likely voters. Nevertheless, we gain much better perspective on the state of the race when we look at all available data.

Alan Abramowitz notes that Obama has consistently led in national polls over the past two months. In fact, according to national poll results listed on, Obama had been tied or ahead in 50 consecutive national polls through Sunday. Sure, many polls may show Obama holding a lead within the statistical margin of error, but if Obama and McCain were actually tied, we'd expect as many polls showing McCain ahead as show Obama ahead. Based on some basic calculations, the probability that 50 consecutive national surveys would show Obama tied or ahead if the candidates were actually tied is .0000000000000009. In short, this race is not a "statistical tie," despite what a few scattered surveys (drawing disproportionate attention from the pundits) indicate.