Four Things to Look for in Post-Convention Polling

Four Things to Look for in Post-Convention Polling
AP Photo/Susan Walsh
Story Stream
recent articles

PHILADELPHIA -- The Republican and Democratic conventions constitute one of the most tumultuous periods in general election polling -- voters are watching the speakers, reading headlines and forming opinions in real time, causing the numbers to change quickly, which is a problem for polls conducted over multiple days.

But once the conventions are over and the dust settles, the polls tend to stabilize and start to give a better sense of which candidate is likely to win the White House in November.

So for those who want to understand the state of the race better, here are four things to watch for as the general election polls roll out:

Does Clinton get a post-convention bounce? If so, how large?

After the Republican National Convention wrapped up last Thursday, Hillary Clinton led Donald Trump in the RealClearPolitics polling average, 44.2 percent-41.6 percent. But, by Monday, Trump had edged narrowly ahead, 44.3 percent-44.1 percent – and, as the Democratic convention went into its final day, he led Clinton by almost a full percentage point.

Trump’s surge in the polls didn’t come out of nowhere -- it’s partly due to what political scientists and data journalists call a “post-convention bounce.” When a party holds a convention, its nominee gets mostly positive, uninterrupted coverage for a week, which helps rally the party faithful and often leads to better poll numbers. After the GOP convention, Trump gained roughly four percentage points in the RCP average -- allowing him to pull into the lead.

Next week, polls should start to show whether Clinton also got a bounce and how large it is. Surveys are often relatively stable in the period between the conventions (which sometimes happen closer to Labor Day) and Election Day. So if Clinton has a large bounce and pulls far ahead, that’s a good sign for her campaign.

But if she fails to get a good enough bounce to tie or pass Trump, that’s a bad sign for her going forward.

Do Clinton’s favorable/unfavorable ratings change?

Trump didn’t just gain in the head-to-head polls after Cleveland. As the convention wrapped up, his net favorable/unfavorable rating was a 25 points more unfavorable than favorable. But today his rating sits at 21.1 points net unfavorable. That’s not an objectively good rating, but it puts him close to Clinton, who sits at a net 17.2 percent unfavorable rating.

The Clinton campaign surely wants to reopen its advantage in these ratings. The economy, the president’s job approval and other “fundamentals” that set the stage for the election suggest a close race or a slight Republican edge. So if Clinton can reopen that gap and become significantly better liked than Trump (or less unliked), she has a better shot of overcoming these underlying forces and winning the presidency.

Where does the convention bounce come from?

It’s also important to understand exactly which voters give Clinton a convention bounce because that might guide her strategy going forward.

Some of her bounce will likely be from skeptical Bernie Sanders supporters. Many of the speeches during the convention -- especially those given Monday night by Sanders and Massachusetts Sen. Elizabeth Warren -- were meant to foster party unity. But some of the later speakers -- Michael Bloomberg, vice presidential nominee Tim Kaine and President Obama -- aimed their message directly at independent and persuadable voters.

So if Clinton’s bounce mostly comes from Sanders supporters, she may devote much of the remainder of her campaign to winning swing voters.

What does the map look like post-convention?

In late June, RCP Senior Elections Analyst Sean Trende noted an odd feature of state polling -- that Trump was performing better than one might expect in swing states but fared worse in traditionally red states. This was really interesting for election wonks because most states have had relatively stable partisan leanings in recent elections. The Trump vs. Clinton matchup looked like it might loosen some of those divisions and maybe make for a more interesting map.

But it’s unclear if the electoral map will stay flattened after the conventions. The GOP gathering rallied many party faithful to Trump, which may help him in red states. And if the Democratic convention reinforces partisan leanings on the left, the 2016 map may look more familiar.

So in the weeks to come, it will be interesting to check on the state polling and see whether this matchup shifts the map at all or if it looks more like a fight between a generic Republican and a generic Democrat.

David Byler is an elections analyst for RealClearPolitics. He can be reached at Follow him on Twitter @davidbylerRCP.

Show commentsHide Comments