Modesty forbids me, but honesty compels me: my 15-month-old predictions for the 2008 Presidential elections have thus far been so spot-on, it's spooky. I know that many of you have clamored for us to drop the science stuff from our blog entirely, and just talk about politics and/or our personal lives, topics that are severely under-served in the blogosphere. My own preference would be to focus exclusively on physics, to the exclusion of any other topic of any possible interest, but who am I, anyway? This is a blog, after all, and I think we can all agree that the loudest commenters should have final say on what we post about. Therefore, I feel compelled to offer up another round of predictions, now that we've narrowed the field to two major candidates. By why not make it more fun and have a prediction contest? Anyone can join in, just by leaving your prediction the comments. Entries that appear before the end of June will officially count. But to make things somewhat science-y, let's use equations to judge who will win. Each prediction consists of two numbers: the fraction f of the total popular vote cast for the two major candidates that goes to Barack Obama, but also the standard deviation σ of your prediction for that percentage. We are thus ignoring the electoral college entirely, and dealing with the annoyance of third-party candidates by concentrating exclusively on McCain vs. Obama. And we are assuming for purposes of misleadingly-precise quantification that each prediction follows a normal (Gaussian) distribution:
$latex displaystyle P(x) = frac{1}{sigma sqrt{2pi}} expleft(-frac{(x-f)^2}{2sigma^2}right) ,.$
And here is the rub: the winner is not the one whose fraction f is closest to the final answer, but the one whose value of P(x) is the highest, when x is equal to the fraction of votes Obama actually does win. The smaller your standard deviation is, the higher your P(x) will be for x very close to your predicted value f , but the faster it will die off as you get further away. So if you are extremely confident, you can ensure victory by choosing an appropriately tiny standard deviation on your prediction. Contrariwise, if you choose a large standard deviation, you might get lucky if none of the confident folks comes close to the actual result. Cool, eh? So here we go: I predict that Obama will win 55.5% of the popular vote fraction, with 1.5% standard deviation. That's right -- a blowout. Might be crazily optimistic of me, but right now the portents are good. In Obama's favor, the current electoral map is extremely favorable (not that it matters for our contest), he is an energetic and charismatic campaigner, his organization is impressively seasoned and effective, he will have twice as much money to spend, Democratic identification among voters is soaring, the incumbent President is world-historically unpopular, various economic crises are putting the squeeze on middle-class voters, the war in Iraq is hugely unpopular, and McCain is a bumbling and unconvincing candidate with a tattered organization, little support among the party faithful, a disturbing penchant for changing his mind and misunderstanding his own policies, and little interest in anything other than foreign policy. In McCain's favor, Obama is black and his middle name is Hussein; also, McCain has a great rapport with the press, who respect his maverick image. Overall, I think the scales are pretty heavily tilted on this one, and I will not be surprised if McCain replaces Bob Dole as the Presidential candidate that Republicans would most like to pretend never happened. Of course, I could be wrong. So let's hear your predictions! The winner will receive a lifetime subscription to Cosmic Variance. Or maybe a T-shirt, if we get caught in a generous mood.
