Explaining Palin's decline in popularity by analogy to the statistical scoring methods of the ball game

In politics, as in baseball, hot prospects from the minors can have trouble handling big-league pitching.

Right after Sarah Palin was chosen as the Republican nominee for vice president in 2008, a friend who grew up in Alaska wrote: "Palin would probably be a pretty good president... She is fantastically popular. Her percentage approval ratings have reached the 90s. Even now, with a minor nepotism scandal going on, she's still about 80%.... How does one do that? You might get 60% or 70% who are rabidly enthusiastic in their love and support, but you're also going to get a solid core of opposition who hate you with nearly as much passion. The way you get to 90% is by being boringly competent while remaining inoffensive to people all across the political spectrum."

This was probably the first and last time you'll ever see the words "boringly competent," "inoffensive," and "Sarah Palin" in the same sentence. Palin got a reputation as a competent nonpartisan governor but when she hit the big stage she shifted to hyper-partisanship.

The contrast is interesting to me as a statistician because it suggests a failure of extrapolation.

In baseball, one of the findings of statistics guru Bill James is that minor-league statistics, when correctly adjusted, predict major-league performance. For a political analogy, consider Scott Brown. When he was running for the Senate last year, political scientists Boris Shor and Nolan McCarty predicted his political position based on his votes in the Massachusetts legislature. They rated him as to the left of most Massachusetts Republicans and, nationally, as slightly more conservative than the moderate Democrats in the U.S. Senate and slightly more liberal than the moderate Republicans there. And that is how he turned out.

If statistics could predict Scott Brown's ideology (and that of many other legislators) based on his minor league performance, why could it not predict Sarah Palin's decline in popularity? To start with, minor league stats need to be adjusted. At the time of her selection as vice presidential nominee, Palin was the fifth most popular governor in America -- but she was from a sparsely populated state, and most of the popular governors are from states with low populations. Being a popular governor of a small state is like hitting .350 in a rookie league: it's impressive, but it's no guarantee of comparable performance in the majors.

So how does baseball differ from politics, in ways that are relevant to statistical forecasting?

In baseball there is only one goal: scoring more runs than the other team. Yes, individual players have other goals: staying healthy, getting paid, and not getting traded to Cleveland, but overall the different goals are aligned, and playing well will get you all of these to some extent.

But there are two central goals in politics: winning and policy. You want to win elections, but the point of winning is to enact policies that you like.

In politics we can try to predict electoral success or ideological positioning. Elections are hard to predict: To continue with the baseball analogy, most politicians get only a few electoral "at bats" in their entire careers, and even the longest-serving may only get a couple dozen chances at the ballot box. But, once in office, they get hundreds of chances to show their positions by publicly voting on legislation. So it makes sense that we can predict Scott Brown's ideology much better than Sarah Palin's popularity. The principles of baseball statistics do hold, if we apply them correctly.

Image credit: Brian Snyder/Reuters