I firmly believe that most political reporters and other "experts" don't know what they are talking about. Few seem interested at all in political history (for example, the parallels that everyone is drawing to 1980 are interesting, but ignore one enormous difference between that election and 2008), in general they are little more than parrots who repeat what they hear from someone else with little thought.
Right now you can read just about everywhere, for example, that John Kerry didn't get any bounce out of the 2004 Democratic Convention. Now if you actually study what happened, you find out that this is actually pretty complicated, but this is far too much trouble for most political reporters.
And so this post will review convention bounces since 1976. At the end I will to suggest how each campaign is likely to play the upcoming month, and who is likely to benefit the most. It is part of a series that I began last summer designed to look at the history of presidential campaigns, To date I have written about how Iowa, New Hampshire, and early summer polling. The last two pieces will be on the debates and the last week of an election. A note: gathering all of this data has been hell, but it does force you to read how the press reported on politics in the past. In general it was every bit as bad as it is today but there is one really significant exception: when E J Dionne covered politics in the late 70's and 80's for the New York Time he was great. I can't think of any current political reporter who shows nearly the knowledge or sophistication he showed on a daily basis for nearly a decade.
A note on this data: Gallup has published calculations that show much smaller bounces than I show here. Their calculations only look at the effect of the party's candidate, and ignore any impact on the candidate's opponent.
The largest bounce was the one Clinton received in 1992. The size of Clinton's bounce is in part a product of Ross Perot's departure from the race.
In the 1970's and 80's networks covered conventions in far great detail than they do know, there were far fewer cable channels that they were competing with. Since Convention Bounces are a largely the result of saturation news coverage, one would expect that these bounces would decline in tandem with the amount of attention given to news coverage. There is evidence that this is happening. The table below compares bounces for incumbents to challengers, and the bounce from the first convention to bounces from the second convention. More importantly though it compares bounces from the 70's and 80's to conventions since 1996. Convention Bounces appear to have substantially declined. Why? There are three possible explanations:
1. The decline in media coverage of the National Conventions
2. The increasing polarization of the electorate
3. The practice of naming running mates before the convention
On the flip I will show how the third explanation accounts for the missing Kerry bounce of 2004