Nate Silver's analysis re: the controversial Ohio poll, indicating a tied race [View all]

[mzmolly]

The most consequential polls of the day were probably in Ohio and Virginia.

The Ohio poll was a good one for Mr. Romney. The survey, conducted by the University of Cincinnati for a consortium of Ohio newspapers, showed the tied race, 49-49, with almost no undecided voters left. The same survey had given Mr. Obama a 5-point advantage before the Denver debate.

Some liberals have critiqued the Ohio poll for being out of date — it was in the field between Oct. 18 and Oct. 23, meaning that some of its interviews were conducted before the final presidential debate in Florida.

I think this criticism is probably overdone. There is little evidence that the race has changed all that much since the final debate; the FiveThirtyEight model finds that Mr. Obama has perhaps gained half a percentage point nationally since then, but probably not much more than that.

And apart from the timing, the poll has a lot going for it: it has a good track record and collected a reasonably large sample size, meaning that it gets a lot of weight in the FiveThirtyEight forecast.

But the poll should not be used to imply that the race is tightening further in Ohio. There have been 12 other polls of the state that also conducted at least some interviews after the Florida debate, and they showed Mr. Obama up by two points there on average, which is about where the FiveThirtyEight forecast now shows the state. If a candidate holds a two-point lead in a state, it is normal for some polls to show him tied or trailing by a point or so instead in contrast to others that might put him four or five points up.

That is pretty much what we see in Ohio right now, with the edge in the polling average remaining with Mr. Obama. The new poll reduced his chances of winning the state to 73 percent from 76 percent in the forecast.

More: http://fivethirtyeight.blogs.nytimes.com/