Oct. 8: A Great Poll for Romney, in Perspective

By NATE SILVER

<...>

There are two smarter questions to ask about the Pew poll. First, is it really likely that Mr. Romney leads the race by 4 points right now? The consensus of the evidence, particularly the national tracking polls, would suggest otherwise. Instead, the forecast model’s conclusion is that the whole of the data is still consistent with a very narrow lead for Mr. Obama, albeit one that is considerably diminished since Denver.

It might be granted that the situation is more ambiguous than usual right now. But our forecast model looks at literally all of the polls; it estimates Mr. Romney’s post-debate bounce as being 2.5 percentage points, not quite enough to erase Mr. Obama’s pre-debate advantage.

The other valid line of inquiry concerns the timing of the poll. The Pew poll was conducted from Thursday through Sunday, although more of the interviews were conducted in the earlier part of that period. There’s nothing in the poll that really refutes the story that Mr. Romney initially received a very large bounce after the debate (perhaps somewhere on the order of 4 or 5 points, if not quite as large as Pew shows it), which has since faded some between the news cycle turning over and the favorable jobs report on Friday.

The evidence that Mr. Romney’s bounce is receding some is only modestly strong — as opposed to the evidence that he got a significant bounce in the first place, which is very strong. Still, the order in which polls are published does not exactly match the order in which they were actually conducted — and at turning points in the race, these details can make a difference

- more -

http://fivethirtyeight.blogs.nytimes.com/2012/10/09/oct-8-a-great-poll-for-romney-in-perspective/