Competing spins over a post-convention ‘bounce’

A week ago, the Bush campaign was trying way too hard to lower expectations about Bush’s poll numbers.

In an e-mail sent Monday, Matthew Dowd, Bush’s chief strategist, predicted that the race will “swing wildly” in Kerry’s favor within a month.

Dowd’s memo included a chart showing that the challenger typically has gained a 15-point bounce in polls when the running mate is announced and the spotlight of the convention shines on the nominee.

These two developments “can have a dramatic (if often short-lived) effect on the head-to-head poll numbers,” Dowd wrote. “In fact, historical analysis suggests John Kerry should have a lead of more than 15 points coming out of his convention.”

Dowd did not say in his memo what factors might help Bush close the gap, or when that might happen.

There’s simply no way Dowd actually believes any of this. It was clearly a way to massage the media and manipulate how observers consider the campaign. If Kerry were to have, say, an eight-point lead over Bush after the convention, Dowd would no doubt say, “This speaks very well for Bush; Kerry’s lead is half of where it should be.”

But this pre-emptive spin isn’t based on reality. As Ruy Teixeira noted the other day, Dowd was spinning so wildly, he basically was arguing that Bush is going to lose.

1. Since 1960, no incumbent president has come back from being 15 points down at the beginning of August to win re-election. In fact, no incumbent’s come back from being 10 points down to win.

2. The average bounce from an incumbent president’s convention since 1960 is about 6 points. Therefore–contrary to Dowd’s assertion that the Republican convention would even things up–a 15 point lead after the Democratic convention would likely leave Bush still 9 points behind after his convention.

Another interesting angle on the Dowd prediction: given that the average bounce from a challenger’s convention is about 7 points, does that mean Dowd now believes Kerry is up by 8 points–since otherwise how could Kerry come out of his convention with a 15 point lead based on “historical analysis”?

Unfortunately, the media has largely bought into Dowd’s spin; I saw the 15-point lead spin everywhere. To help offer a more realistic analysis, Kerry’s staff put together a more likely post-convention scenario.

Despite the high ratings for the Edwards pick, we do not anticipate a substantial bounce in the horserace as a result of either the selection, or the convention. Challengers sometimes get convention and Vice Presidential selection bounces because they have not consolidated their partisan base. Most recent polls show John Kerry already getting 82%-89% of the Democratic vote. Thus, there is little base left for John Kerry to consolidate. He has already accomplished that goal.

Good point. Historically, wavering partisans coalesced around their party’s candidate after the convention, helping the nominee get a bump in the polls as previously “undecided” voters joined the fray. Nationwide, Dems have already done this; it will mean a far smaller bounce.

The campaign also offered a helpful assessment of Kerry’s strong standing before the convention even starts.

[E]ven before the convention and his selection of John Edwards, John Kerry was already in much stronger position than most challengers have been coming out of their conventions. Since 1956, on average, elected incumbents have gone into the Vice Presidential selection and convention season with a 16.6 percentage point lead. Bush strategist Matt Dowd admits that, at worst, Bush and Kerry are even. This puts Kerry far ahead of where other challengers have been going into their conventions, and puts Bush far behind the traditional mark.

[…]

Indeed, only three incumbents in the past 50 years have been behind the challenger after the challengers’ conventions — and all three have ended up losing on Election Day (G.H.W. Bush, Carter and Ford).

Something to keep in mind the next time you hear pundits wondering aloud why Kerry’s lead isn’t bigger at this point.