Field of Science

How to predict an election? Ask the math geeks.

Mark Newman's rendering of the 2012 U.S. election,
 weighted by population

It's time for a bit of gloating.  No, not for Democrats over Republicans, though I'm sure that's going on.  It's time for the math geeks to throw a bit of scorn at those insufferable, over-confident frat boys who call themselves political prognosticators, and who spent most of the past two years telling us that they knew how the election would turn out.  They bloviated endlessly on talk shows, explaining why their favored candidate would win, and how he would do it.  

Politicos behave just like promoters of quack treatments when things go wrong: they always have a ready answer, and somehow their "theories" can never be proven wrong.  It seems that the only thing these guys are really expert at is getting themselves onto talk shows. Now that the election is over, let's hope that happens a bit less often.

Instead, pay attention to the math geeks.  The statisticians and analysts who build mathematical models based on multiple polls and other data absolutely nailed this election.  Nailed it!  Nate Silver at FiveThirtyEight blog predicted the winner of the presidential election in all 50 states.  So did Sam Wang , a biophysics professor at Princeton, over at the Princeton Election Consortium blog.  And so did Simon Jackman, a political science professor at Stanford who writes for HuffPo.  Nate Silver first drew everyone's attention in the 2008 election, when he correctly predicted 49 out of 50 states.  Last week's success shows that this is not an anomaly, although it has the mathematically challenged pundits in a tizzy.

Hopkins statistics professor Jeff Leek wrote a nice explanation of how these models work over at Simply Statistics, so I won't explain it here.  Suffice it to say that mathematical models don't work by chattering with their buddies at political rallies.

Mathematics delivered the goods.  And make no mistake, this is the way of the future.

That hasn't stopped the punditocracy yet.   On election night, Republican hatchet man Karl Rove was sputtering on Fox News that Romney could still win, after Fox News itself - which is little more than a media arm of the Republican party -called Ohio and the election for Obama.  Rove, who predicted that Romney would win with 285 electoral voites, also orchestrated the spending of over $127 million on Romney, not to mention his spending on 12 Senate candidates, 10 of whom lost.  Has he admitted he did anything wrong?  Nope.

Rove wasn't the only one wrong.  As Techcrunch pointed out
"every single major pundit was wrong - some comically wrong."  
The Atlantic created a detailed score sheet listing all the pundits and their predictions of the overall winner, the electoral college total, and the winner in all the swing states.  And indeed, even those who predicted correctly that Obama would win got most of the swing states wrong.

Here's what needs to happen.  The television networks need to realize that political expertise is meaningless when it comes to making statistical predictions.  Let's treat political forecasting just like weather forecasting, using models that are demonstrably accurate (such as Silver's).  Television stations can hire attractive political "forecasters" (because physical appearance matters on TV, like it or not) who will describe the latest forecasts just like today's weather forecasters do.  Now that I think of it, why not let the weather forecasters do both jobs?  We already have them in place at every local TV station in the country.  Think of all the money the networks will save.

But what about all that air time they need to fill with talking heads arguing about who will win elections?  Well, this makes about as much sense as having two self-proclaimed experts arguing about whether it's going to snow this weekend.  Maybe they can find real experts who will argue about issues rather than about who's ahead in the polls.

Ha ha, just kidding!  Who wants to hear about issues?  But if you must know how the race is going, ask the math geeks.

3 comments:

  1. You seem to be laboring under the misguided impression that news programs/networks are designed to inform. They are designed to sell advertising, which they can do only if they attract viewers. But viewers don't want a dry explanation of the facts; viewers don't really want the truth. And when the conclusion of those facts can be described in less than a minute, such coverage would be very boring. Viewers want someone to tell them that their guy is going to win. But to create the facade of impartiality news programs, whether at FOX or MSNBC, must permit dissenting views as well. An additional benefit for the networks is that "experts" can argue for as long as the networks have air to fill. Ultimately, people want to live in their bubbles and until human nature changes, I wouldn't expect statistics to get much coverage on FOX.

    ReplyDelete
  2. It is worth noting that it is not enough to use math and statistics, you have to use it correctly. Here is a link to a paper by Michael Berry and Kenneth Bickers of the University of Colorado:

    Berry's Paper as PDF

    This paper was still being lauded by some media outlets up to the week before the election. The authors built a statistical model with "100% accuracy" that predicted Romney would win the election. You can learn all you need to know from tables 1 and 2. In table 1, the authors train a model on the outcome of elections from 1980-2008. In table 2, the authors show that they can use the model to predict with 100% accuracy... the outcome of elections from 1980-2008! Arghhhh! This sort of thing really shouldn't make it past peer review. If you want to know the accuracy of a model, you cannot determine it by testing it on the same data you used to train it. There are easy ways to do this correctly even with small data sets, like leave one out cross-validation. In addition, table 1 shows that the authors included three variables that are not statistically significant, another no-no. One of those three variables is a combination variable: Democratic Incumbent * State Unemployment Rate. This variable seems tailored to fit the authors' initial assumptions that Obama will lose because of the economy.

    ReplyDelete
  3. I’m so glad you wrote about this. My daughter was having full-blown anxiety attacks before the election and couldn’t see how I was so calm. “I’ve been reading Nate Silver”, I replied, “and his work is science based, whereas the pundits are just psychics and tarot card readers” I added. Also, I don’t own a TV for largely the reasons commenter Bend relates. I do watch Netflix on the computer in case anyone is thinking I’m Amish or something.

    Thanks to you and ScienceBasedMedicine, I’ve become an even better skeptic. Many thanks.

    ReplyDelete

Markup Key:
- <b>bold</b> = bold
- <i>italic</i> = italic
- <a href="http://www.fieldofscience.com/">FoS</a> = FoS