All eyes on—where else?—Ohio

Since the final presidential debate, 15 polls have surveyed voter opinion in Ohio, the state that is more likely than any other to determine the election. President Barack Obama leads former Gov. Mitt Romney in 13 of them. The candidates tied in one, and Romney leads in one. Those last two polls were both conducted by Rasmussen, one of the more right-leaning polling institutions, as FiveThirtyEight's Nate Silver has documented.

No one is saying Ohio is a walk for the president. The Huffington Post's Pollster and the RealClearPolitics average both have Obama leading with 51.2 percent among those who express a preference for either major candidate. There is still time for a shift toward Romney, and it's always possible that there is a systematic bias in the polls.

But I don't think it's likely. Historically, polls have been pretty accurate this close to the election. Based only on these surveys, the Signal gives Obama a 75 percent chance of victory in Ohio. When we factor in prediction markets, that figure ticks up a small amount, to 77 percent.

All is not lost for Romney. A 25 percent likelihood of winning Ohio is far from negligible, though that value is likely to diminish with each day that elapses, because most of the uncertainty in this prediction is over what can happen in the next five days. Romney does not need a miracle, but he should hope at least for a very good roll of the dice.

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David Rothschild has a Ph.D. in applied economics from the Wharton School of Business at the University of Pennsylvania. Follow him on Twitter @DavMicRot.