Nate Silver: “Harris is ahead by 3.8 points in our national poll tracker — up from 2.3 points the day before the Democratic Convention began — which does suggest some sort of convention bounce. However, she’s fallen to a 47.3 percent chance of winning the Electoral College versus 52.4 percent for Donald Trump. (The numbers don’t add to 100 because of the possibility of an Electoral College deadlock.) Some of this is because of the convention bounce adjustment that the model applies to polls that were conducted during or after the DNC. It assumes Harris’s polls are somewhat inflated right now, in other words — just as it assumed Trump’s numbers were inflated after the RNC.”
“While there’s a solid basis for this empirically, you could argue we’re under unusual circumstances because of her late entry into the race. So if you want to treat all of this as a little fuzzier than usual, I don’t really mind that. The good news for Harris is that if she merely holds her current numbers for a couple more weeks, she’ll begin to track up again in our forecast as the model will become more confident that she’s out of the convention bounce period.”
“There’s another, longer-term concern for Harris, though: it’s been a while since we’ve seen a poll showing her ahead in Pennsylvania, which is the tipping-point state more than a third of time in our model. Today, in fact, we added one post-DNC poll showing Pennsylvania as a tie, and another (conducted during the DNC) showing either a tie or Trump +1, depending on what version you prefer.”
