Don't Count On the So-Called 'Post-Convention Bounce'

Folks are speculating on the size and impact of the "bounce" coming out of the GOP convention in Tampa.

For example, Frank Newport has this, at Gallup, "No Signs of GOP Convention Bounce Yet" (via Memeorandum). And from wonderboy Nate Silver, at New York Times, "Sept. 2: Split Verdict in Polls on Romney Convention Bounce."

But while getting a big bounce would be nice, the fact is such polling surges are rare.

See Dante Chinni, at the Wall Street Journal, "Politics Counts: Don’t Read Too Much Into the Bounce":

With one convention down and one to go, the great game of bounce analysis is afoot. Over the next few days and weeks the media will scour polls to try to figure who “won” the political convention battle.

The better question may be how much it all matters in the end.

Conventions are important events in presidential campaigns. They provide each of the two major parties the chance to have the media largely to themselves and lay out their beliefs, as they see them, to the public. And they give the major candidates at least one night where can have an hour or so to speak directly to the American people in a presidential setting – or at least a semi-presidential setting, an arena filled with supporters cheering him on.

And, as we noted on Thursday in this space, when you get inside the numbers using the geographic/demographic Patchwork Nation breakdown of counties, there are some post-convention trends worth watching. In the coming weeks one critical question is whether GOP nominee Mitt Romney can win over voters in Republican-leaning communities like the small-town Service Worker Centers (in red on the map below) and the aging Emptying Nests (in light green). Mr. Romney will need them in November.

But in the end, the conventions are moments that pass. And even though they have migrated closer to the fall in recent years, they still are far enough away from Election Day to allow for plenty of change afterward, particularly in the modern media environment.

Remember the excitement that followed former Alaska Gov. Sarah Palin’s speech in St. Paul in 2008? It seemed like ancient history by October.

So what’s in the bounce? It can depend a lot on the year and the campaign, but on the whole, the answer is usually less than meets the eye.

On average, Gallup says the typical post-convention bounce is worth about five percentage points. There have been notable exceptions, such as former President Bill Clinton’s 16-point bump after the Democratic convention in 1992, though as most everyone points out, that also followed independent candidate R. Ross Perot dropping out of the race. And in 2004, Democratic nominee Sen. John Kerry got a negative bounce after his convention, a net drop of one point.

But more important than any post-convention bounce is a candidate’s ability to maintain or even grow whatever advantage they get out of their week of being front-and-center in the media. And using that measuring stick, the much-discussed bounce seems a bit over rated as recent examples show.

More at the link.