Nate Silver on Obama's big post-convention bump

Nate Silver:

The most impressive thing that our model did in 2008, in my view, was not in “calling” all but one of the states right on Election Day. There was very little doubt about who was favored in perhaps 46 or 47 of these states. The other three or four were tossups — and whether you guessed the winner right had as much to do with luck as skill. 

Rather, it was what the model did in September of that year, when it detected very, very quickly after the collapse of Lehman Brothers that John McCain’s goose was cooked, with Barack Obama’s projected probability of winning the Electoral College increasing by about 25 percent in a period of just 48 hours. 

We’re not seeing anything quite that dramatic in the polls right now. Nevertheless, the polling movement that we have seen over the past three days represents the most substantial shift that we’ve seen in the race all year, with the polls moving toward Mr. Obama since his convention. 

How far will Mr. Obama’s numbers rise, and how long will his bounce last? We don’t know that, of course. But the range of possible outcomes reads pretty favorably for him.