As you're surely aware by now, most polls taken after the conventions ended have shown Hillary Clinton surging to a sizable lead over Donald Trump. But write-ups of these polls have often been accompanied by the caveat that polling is volatile in the immediate wake of the conventions. A bounce for a candidate might not end up lasting.

So when, you might wonder, should we really start trusting the polls again?



The answer: right about now.



We are two weeks out from the final day of the Democratic convention. And according to historical research by political scientists Robert Erikson and Christopher Wlezien, this is usually the time that the convention fog finally lifts and the polls become more predictive.



"Although the convention season is the time for multiple bounces in the polls, one party ends up with an advantage when the dust clears. And this gain is a net convention bump rather than a bounce," Erikson and Wlezien write in their book The Timeline of Presidential Elections.



That is, once the volatility dies down, one candidate usually emerges from the convention chaos with a durable lead. And almost always, the political scientists find, that candidate goes on to win the election.

