Nate Silver and Micah Cohen had an interesting piece last night about the extraordinary volatility in polling during the invisible primary this year; turns out that the three most volatile candidates ever (since 1984 at least) were Newt Gingrich, Herman Cain, and Rick Perry this year, and even Michele Bachmann finished an impressive seventh, while at the same time Mitt Romney and Ron Paul both wound up on the all-time top ten most stable list. Interesting!
Silver attributes it to campaign organization, or rather the lack thereof for the unstable group. Without strong campaign organizations, they're more dependent on media attention, which comes and goes.
Plausible! But then again, two of the candidates on the most-volatile list, Howard Dean 2004 and Bill Clinton 1992, had pretty strong organizations. Not saying he's wrong, but a couple of other things occurred to me as I looked at his list. Also, it's not quite clear from the article whether which polls we're looking at, but if it's national polling then it's hard to see how organization would have much effect on the bulk of voters, since there's so little early organization in large, late-voting states.
My guess is that volatility is an effect of the lack of free parking. Let me explain. Most voters aren't focused on the nomination race at all during the year before the election. Therefore, they'll park their vote -- in the unlikely event that they need to, which is one of the effects of a pollster asking the question -- with the first candidate they can think of. When there's a heavyweight candidate, they park there and stay there; in fact, they'll likely stay there right through their primary, whenever it is. Otherwise, it's going to be whoever has been in the news latest, which moves around a lot. So I'd expect a lot more volatility when there's no obvious place for inattentive voters to park their votes.
If heavyweight candidates are people who were recently (last couple of cycles) on a national ticket, then we are talking about on the Democrats side 1984 (Mondale), 2000 (Gore), 2004 (Lieberman) and 2008 (Edwards, plus a First Lady ad hoc inclusion for Hillary Clinton). On the Republican side, 1988 (Bush)...and that's it, although subjectively I'd certainly include 1996, with Dole a three-time candidate, the previous runner-up, and a former VP nominee.
Going to the chart, eight of the most-volatile candidates are from years with no heavyweight. The stable candidates include the three big names from the 2008 Democratic contest, and one other, so four for ten.
But of course the problem is how to account for Ron Paul and Mitt Romney this year. The clue? Perhaps it's 2008 stable candidate John McCain (although -- really? that's not my memory of it...might be an artifact of the particular months they're using). The answer might be that repeat candidates are less likely to exhibit wild swings. Accounts for Pat Buchanan 1988, too, if you don't like my rigging that year by including Bob Dole as a heavyweight. That makes sense: people who haven't yet focused on the current cycle will bring their leftover feelings from the last cycle, therefore either parking their support with a candidate they remember liking or being more resistant to minor fluctuations in publicity for that candidate if they don't like him or her. Note that Edwards 2008 is on the stable list, which makes four of ten stables as repeat candidates, compared with zero for ten on the volatile list.
If I played with it a bit more...it doesn't affect the results here that much, but 2004 for the Democrats certainly turned out to behave more like a year without a heavyweight. It's possible that the quicky formula I'm using here could be tweaked to exclude Lieberman...although of course you need to be very careful about that sort of thing. I would exclude Dan Quayle's 2000 campaign, since he withdrew during the period that Silver and Cohen are using.
So that's my guess. Volatile/stable in the year before voting is a function of two things: whether there's a heavyweight in the field, and whether the candidate has run before. I strongly suspect that if Silver and Cohen run that on their database, those are going to be the big drivers, even if they had a good measure of campaign organization and tossed that in.