Media and Momentum

In my last post I mentioned that I thought part of the explanation for Obama's meager convention bump was that the Palin announcement on the day after the convention robbed Obama/Biden of much of the post-convention media coverage that might otherwise have benefited them. The more general thought along these lines is that convention bumps are the product of candidates dominating news cycles for a period of several days. This is what I found when I wrote Do Campaigns Matter? and I suspect the same holds true today.

The data below illustrate the ebb and flow of media coverage from early August through mid-September (the dots represent daily observations and the line is the smoothed--lowess--trend estimate). These data do not capture the tone of coverage but rather the extent to which one candidate or the other dominates news coverage. It's possible, of course, that more coverage could be due to negative stories, but it strikes me that the coverage around the conventions is mostly beneficial to the convening party.


There are a couple of important observations to draw from this figure. First, Obama's media presence peaked during the Democratic convention and then bottomed out immediately after the convention's end. It certainly seemed at the time that Obama and Biden disappeared following the the convention, and these data show that that was the case. On the Republican side McCain enjoyed a media advantage during the Republican convention and generally has managed to maintain a slight edge in coverage in the weeks since the convention. Although McCain's advantage is slight, he was able to extend the level of coverage from the convention for a longer period than was Obama.

The other interesting finding here is the degree to which Obama dominated media coverage in the pre-convention period. During the period from August 1 to August 24 Obama averaged 57.4% of all candidate news mentions; and with the exception of a single day (August 15) Obama led in news mentions during the entire period. This lends some credence to the McCain campaign's refrain from earlier this summer that the media were providing much more coverage of Obama than McCain. However, whereas Obama clearly drew more coverage in the pre-convention period, the post-convention period is more balanced.

Note: the data for media coverage come from perspctv.com, a web-based news and information aggregater.