Hillary Clinton continues to poll strongly in surveys conducted after the Democratic National Convention, which show her having received a convention bounce and gaining a meaningful lead over Donald Trump. The polls are coming in quickly enough that it’s somewhat futile to tick them off one by one, but here are some highs and lows as of 10 a.m. Eastern Time on Tuesday:
- Clinton’s smallest lead in any fully post-DNC national survey is 5 percentage points.1 She achieved that 5 percentage point lead in several polls, such as this one from Public Policy Polling.
- Her largest lead is 15 points, in a poll from RABA Research. That poll is something of an outlier, though, with most polls showing Clinton’s lead in the 5- to 8-point range.
- Clinton’s largest bounce in any national poll, as measured in comparison to another survey by the same pollster conducted with a full set of interviews after the Republican National Convention, is 13 percentage points. That comes from a CNN survey, which showed her turning a 5-point deficit into an 8-point lead.
- And her smallest bounce in any such survey is from YouGov, which had her lead growing from 2 percentage points to 5 points, a 3-point bounce.
There are some hints that Clinton’s post-convention lead over Trump will eventually settle in at about 7 percentage points, give or take a couple points. The biggest tip-off is that both the national polls and the state polls we’ve seen so far look similar to the ones we were seeing in June, when Clinton maintained a lead over Trump of about 7 points after wrapping up the Democratic nomination. Since Clinton and Trump were roughly tied after the GOP convention, a 7-point lead for Clinton would mean she’d gotten about a 7-point bounce, double the size of Trump’s.
FiveThirtyEight’s forecast models aren’t used to seeing a lot of 7-point overnight shifts, which rarely occur outside the conventions. (In recent elections, they’ve also rarely occurred during the conventions, with most convention bounces looking more like the modest one Trump got.) So the models may still need another day or two to catch up.
Our hyperaggressive now-cast, which describes the results of a hypothetical election held today, will be the quickest to adapt: It already shows Clinton with a 5.6 percentage point lead over Trump. Be wary of getting too attached to the now-cast, however. It is useful in situations like these, where you want a quick read on how a news event has affected the polls, but it can also jump around a lot on the basis of statistical noise or short-term aberrations in the polls.
The polls-plus model is also relatively well-equipped to handle the new data. Clinton probably has some further room to grow in this forecast, but because it adjusts for potential convention bounces — adjusting post-RNC polls upward for Clinton, and post-DNC polls downward — the shifts won’t be as dramatic. Furthermore, the polls-plus model discounts the polls by blending them with a “fundamentals” forecast, which suggests the race should be close because of economic conditions. This leads to a fairly stable forecast: Clinton’s chances of winning the election have never been lower than 59 percent, or higher than 73 percent, according to polls-plus. As of 10 a.m. Tuesday, they were 69 percent, up from about 60 percent before the DNC began.
Lastly, there’s our polls-only forecast, which shows Clinton with a 66 percent chance of winning. Usually, the polls-only model is a nice compromise, making fewer assumptions than polls-plus but being less hyperactive than the now-cast. But during the conventions, it’s the most stubborn of the bunch, being reluctant to reverse itself after having shown a clear trend to Trump throughout July. Clinton’s lead over Trump in polls-only will probably continue to grow over the next several days, provided she continues to get polls showing a bounce.
But the more important question is not how long it will take Clinton’s bounce to show up in the polls — or our models — but how long she’ll sustain it. If Clinton maintains a clear lead over Trump in the polls by Labor Day, she’ll be in a strong position that has historically translated into a high probability of winning.
Clinton’s bounce is more likely than not to fade some by then, if historical patterns hold. But the change may not be all that dramatic; historically, the polls are most askew in between the conventions, when one party has had the chance to make its pitch while the other one has not, as opposed to after both conventions. There have even been some elections, such as 1988, when the incumbent party seized the lead during the conventions and it continued to grow during the stretch run.
Perhaps the biggest question of all is whether we’ve reached some new equilibrium in the race, when one was lacking before. After the DNC ended, I wrote the following:
What’s tricky about 2016 is that we don’t have a strong sense of what that equilibrium looks like. “Fundamentals” models like the ones that predicted Bush would beat Dukakis suggest that this election ought to be close, since the economy and President Obama’s approval ratings are about average. But those fundamentals-based models don’t have all that good a track record, and they potentially have trouble accounting for the effects of an unusual candidate like Trump.
We can look to the polls instead, but the news cycle has constantly been in motion, and therefore the polls have been in motion, as well. Trump gained on Clinton after wrapping up the Republican nomination in May. Clinton rebounded to take a clear lead once the Democratic campaign officially ended in June. The polls held relatively steady for a few weeks, but Clinton’s numbers began to decline again after FBI Director James Comey’s repudiation of her use of a private email server while serving as secretary of state. There have also been a lot of tragic and chaotic events over the past month, such as the Dallas shootings of police officers and the terrorist attack in Nice, France, which potentially play into Trump’s narrative about a world spinning out of control. And now Trump seems to have gotten a modest convention bounce. […]
But just perhaps, this convention will reveal the true colors of this race, when other events have failed to do so. If Clinton vaults to a 9 percentage point lead, or if she doesn’t get a bounce at all, that will be the clearest sign to date of where the race is headed.
It doesn’t quite look like Clinton will reach the 9-point lead, but it could be pretty close, especially if Trump continues to reinforce Clinton’s convention themes by behaving erratically. (Usually, a convention bounce plateaus just a few days after the convention, so if Clinton’s lead is continuing to grow into next week, that will suggest Trump’s post-convention antics are worsening his problems.) Clinton and her Democrats may simply have the more broadly appealing message, whereas Trump doubled down at his convention on appealing to his predominantly white, working-class base, a smaller share of the electorate than you might think.