Is McCain within margin of error?

SUMMARY: McCain claims he's "within the margin of error," but that's true only for the Fox poll.

Sen. John McCain sounded upbeat in a Halloween morning interview on CNBC. But was the enthusiasm just a mask?

We can't be sure. But we can check some data McCain cited to justify his optimism.

"I'm very optimistic, and we're coming from behind," McCain told anchor Larry Kudlow in the Oct. 31, 2008, interview. "I'm the underdog. There's where we always like to be. But we are within the margin of error, my friends. And I'm very happy where we are."

McCain was clearly talking about national polls, which are not necessarily indicative of Electoral College results. Nevertheless, only four presidents have won the election without winning the national popular vote — John Quincy Adams in 1824, Rutherford B. Hayes in 1876, Benjamin Harrison in 1888 and George W. Bush in 2000.

So we looked at every national poll we could find from the past two days to see if McCain really is within the margin of error.

Five polls were released the same morning McCain was speaking. Rasmussen's daily tracking poll  showed Obama up 51 to 47 with a margin of error of plus or minus 2 percentage points. The Diageo/Hotline tracking poll had Obama up 48 to 41 with a margin of error of 3.3 percent. The Reuters/C-SPAN/Zogby poll showed Obama up 50 to 43 with a margin of error of 2.9 percentage points. Research 2000/Daily Kos had Obama up 51-45 with a 3-point margin of error. And an Associated Press-Yahoo News poll showed Obama up 51 to 43 with a margin of error of 3 percentage points.

McCain was not within the margin of error in any of those five. But they all came out the morning McCain spoke. So to be fair, let's look at the polls released the previous day, Oct. 30.

A Washington Post-ABC News poll showed Obama leading 52 to 44 with a margin of error of 2.5 percentage points. The New York Times/CBS News poll showed Obama leading 51 to 40 with a margin of error of 3 percentage points. The Investor's Business Daily/ TechnoMetrica Institute of Policy poll showed Obama leading 47.7 to 43.6, with a margin of error of 3.5 points. The GWU/Battleground poll showed Obama up 49 to 45 with a margin of error of 3.5 percent. The Gallup daily tracking poll had Obama up 50 to 45 with a traditional model of turnout, and 51 to 44 with an expanded turnout; both have a 2-point margin of error.

So McCain was not within the margin of error in any of those either.

In fact, McCain was not within the margin of error in any national poll we could find from the past two days — with one exception. The Fox News/Opinion Dynamics poll released Oct. 30 showed Obama leading McCain 47 to 44, with a 3-point margin of error.

Some liberal critics of Fox News have raised the possibility that the network cooked the poll to create momentum for McCain. Other analysts have said the poll is more likely "statistical noise."

It's important to note that the law of probability dictates that there will always be outlier polls. As Charles Franklin, professor of political science at the University of Wisconsin, Madison and co-developer of Pollster.com told us recently, "You shouldn't get too excited about one unusual poll."

McCain may have gotten a little too excited about the Fox poll. It's true that he was within the margin of error — but he failed to mention that was only in one poll. We find his statement Barely True.