Josh Green had a fascinating story the other day about the difference between the Obama campaign's (accurate) internal polling data and Gallup's wildly off-base data. He delves into exactly how Gallup thinks they got it wrong, but looking at the chart I'm struck by how good Gallup's polling was at doing what Gallup's polls are supposed to do—drive media interest in Gallup polls.
You see two big things from the Obama campaign data. One is that on a day-to-day basis nothing matters and nothing changes. The people who follow campaign events are mostly strong partisans whose minds don't change, the swing voters whose minds might change aren't interested in politics so they don't know these things are happening. Even worse, the Obama data shows that even the things that do matter don't actually matter. The "bumps" Obama got from the Democratic Convention and the 47 percent tape were almost precisely offset by Obama's terrible performance in the first debate. This is a picture of how US presidential campaigns play out that's validated by scholarship on the history of elections, so it should give us some confidence that the Obama team knows what they're doing.
But what they're doing isn't what Gallup is doing which—again—is trying to drum up media interest in Gallup polls. And compared to the Obama numbers, the Gallup numbers are really interesting. You could write lots of articles about those numbers, while the Obama numbers tend to suggest that you shouldn't bother.
I'm not a huge fan of the "we should be gambling all the time about everything" school of thought, but it would be useful in this realm. If public polls were released by people who were placing large financial bets on the outcome of the campaign, then pollsters would work to purge their models of excessive volatility. But in the world that exists, the incentives are all wrong. "Incumbent President presiding over economic growth and falling unemployment will probably win and nobody's paying attention to the campaign" is a terrible news story. It just happens to be true.