As you might have heard, the presidential election is tomorrow. As I’ve said, I believe I’m alone on ScienceBlogs as supporting anyone but Obama. But this is Built on Facts, not Built on Wishful Thinking, and so let’s have our official quadrennial Election Prediction Contest!
Here’s the plan. We’re predicting three quantities of interest.
1. Electoral Vote
2. Senate Seats
3. Popular Vote (in percent)
We’re not going to bother with the house, since raw numbers aren’t as important. A house with 59% Democrats is only marginally different than one with 61% Democrats. In the senate on the other hand, a 59 seat majority versus a 61 seat majority can make a world of difference. So if you’d like to participate in the predictions, this will be the plan. The electoral vote number is the number of electoral votes Obama gets. You can include McCain’s number as well especially if you think a third party will get any votes. But if you do, make sure you note which number is which. The senate seats category is the number of seats held by the Democrats. Assume the Independents continue to caucus with the Democrats. The popular vote category is the percentage of the popular vote held by Obama and McCain respectively. They shouldn’t add to 100% because of the smaller parties, so you’ll probably want to take that into account.
My predictions (try to format yours at least roughly along these lines):
1. 338 Obama EVs.
2. 58 Democratic senate seats
3. 49.0% Obama, 45.0% McCain, 6% other.
Thus each prediction involves five numbers, one for each of the first two categories and three for the popular vote. Scoring will work like this. Once the actual numbers are known, for each of your guesses, take the actual result and subtract your guess. Your goal is for the following expression to be as small as possible:

It only uses your first two guesses, the popular vote is there as a tiebreaker. Note I’ve weighted the senate score somewhat on the grounds that the possible spread in EVs is much higher than the possible spread in senate seats. On the off chance more than one person has the same guess for all three (for instance, if someone copies) the tie is broken in favor of the earlier poster (I disqualify myself, by the way). Sadly there’s no prize other than the knowledge of a job well done.
Where does my 338 number come from, by the way? Start with the 2004 map and give Obama these states: CO, FL, IA, NV, NM, OH, VA. I don’t think he gets Missouri or North Carolina, but those are the two states I think I’m mostly likely to be wrong about.
What’s the chance the McCain pulls out a victory? According to Intrade yesterday, it’s about 1 in 8. According to FiveThirtyEight yesterday, it’s about 1 in 26.
So let’s have your guesses! If possible try to keep mostly on topic about what you think will happen. There’s the rest of the internet for arguing about which result you think is better. I’m going to close comments on this post at around midnight tonight so there can be no late entries. Good luck!