Could Clinton get a 10-point bounce? Or no bounce at all? Sure — we don’t know enough about convention bounces to rule out either possibility. It’s not even clear whether convention bounces have to do with the efficacy of the conventions or the underlying conditions of the race (or some combination). Bounces seem to be larger in years when there are more undecided and third-party voters. They seem to be larger in years when the polls are more volatile heading into the conventions. Both those factors might portend larger bounces this year, since there are a lot of undecideds and the polls have been fairly volatile. On the other hand, bounces have gotten smaller over time, and perceptions of Clinton and Trump are relatively hard-wired as compared with those of typical presidential candidates…

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 B. 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.1