What Too Close To Call Really Means

http://campaignstops.blogs.nytimes.com/2012/10/30/what-too-close-to-call-really-means/

I am a political statistician, or, perhaps I should say, a statistical political scientist [..] And for months I’ve always said, either side could win it.

Obsession with this question is not confined to the United States. Last week I was interviewed by a reporter from France, who asked me who I thought would win the election. I said, it’s too close to call. He said, but Nate Silver’s FiveThirtyEight blog on NYTimes.com currently gives Obama a 72.9 percent chance. I think Nate is great, and I was thrilled to have the opportunity to contribute to his blog for a while. But I’d still say the election is too close to call [..]

Let’s dig and see what this means. If we ran the election 100 times, Silver was saying that Obama would win 72 of them — but we’ll only be running it once. Silver was predicting an approximate 50.3 percent of the two-party vote share for Obama, but shifts of as large as 1 percent of the vote could happen at any time.