Nate Silver: Biden did not get much of a convention bounce, and a net negative in forecast

In a series of tweets, 538’s Nate Silver explains how Biden does not appear to be getting much of a convention bounce and the direction of swing state polling is not looking great for him either.

In the 538 “Chance of Winning” forecast, President Trump’s chances of winning has actually increased to 30 in 100 from August 17th the start of the DNC when it was 27 out of 100.

Silver writes “First, Biden does not appear to be getting much of a convention bounce. He’s at +8.8 in our national poll average (still quite good) but that’s only up from +8.4 before the conventions.”

“Our model expected pretty small bounces this year, but still it sees this small a slight net negative for Biden, as it adjusts polls taken during what’s supposed to be Biden’s convention bounce slightly downward.”

“Second, Biden has gotten some not-so-spectacular swing state polls lately. His lead in Florida is down to +5.4 and in Pennsylvania to +5.8, which remain the most likely tipping-point states. Not bad, but the Electoral College – popular vote gap would appear to be widening a bit.”

“The BIG caveat is that this is not based on the world’s most spectacular set of polling, especially at the state level. And almost of it is online panels, with a robopoll thrown in here and there; basically no live caller polls since the pre-convention round from ~10-14 days ago.”

“That matters more during the conventions than it might ordinarily, because online panel surveys tend to make assumptions that can flatten out bounces, whereas live-caller polls tend to show bigger swings after major events.”