As Republicans gather next week in Cleveland for their convention and Democrats prepare for their big show the following week in Philadelphia, both parties look to reset their campaigns for November. What type of “bounce” in the polls will their presidential candidates get from these primetime events?
According to Gallup, the post-convention bounce has varied from election to election since 1964 to 2012. Some candidates (Johnson in 1964, McGovern in 1972, and Kerry in 2004) saw minimal poll movement, while other candidates (Goldwater in 1964, Nixon in 1972, and Clinton in 1992) saw large bumps. Between 1964 and 2012, Democratic presidential candidates have seen on average a 5.8 percentage point increase after their conventions, while Republicans have enjoyed an average 4.9-point jump. The numbers have varied significantly in the recent elections. In 2008, Sen. Barack Obama’s poll increase was four points, while Sen. John McCain’s standing improved by six points. In 2012, however, Mr. Obama only had a three-point jump and Mitt Romney’s numbers remained virtually unchanged.
The year’s unpredictable primaries and the placement of the conventions a month earlier this cycle than they have been in recent years help make 2016 a different kind of election. How these factors affect the “bounce” remains to be seen.
However, a big post-convention bounce jump does not mean certain victory. Just ask Jimmy Carter. He received the bigger bounce (10 points compared to Reagan’s 8) after the 1980 Democratic convention, but lost a few months later.