With all of the votes counted(Well, except Minnesota), Stochastic Democracy analyzes how well it's model's predictions did vs Nate Silver's FiveThirtyEight and Pollster.com
See below the fold for details, or click through the site to see the results interactively
StochasticDemocracy.Blogspot.com
Now that it seemsclear that Democrat Al Franken is going to win the Minnesota Senate race, and with every state having certified their final vote totals, we can look at how accurate Stochastic Democracy fared this election cycle:
Electoral College:
Having some fun...
Our model correctly predicted the winner of the presidential race in every state except Indiana(Where we predicted Obama had a 48% chance of victory).
In terms of electoral votes, our model predicted that Obama would win 364 electoral votes, when he instead won 365.
Altogether, we called 50 out of 51 states/districts correctly, and our electoral forecast was off by 1 vote.
National Vote:
We predicted that Obama would receive 53.76% of the two-way vote. He went on to win 53.68% of the vote.
So our prediction was off by 0.09% , less than a tenth of a percent.
Senate and Governor:
We correctly predicted the winner of every senate race, as well as predicting that the Georgia Senate race would go to a run-off.
We also correctly predicted the outcome of every Governor race.
Comparison with FiveThirtyEight:
In terms of predicting winners, FiveThirtyEight and our site produced nearly the same predictions. The only differences were:
- Due to the lack of polls, we did not provide a forecast for the Omaha district of Nebraska. FiveThirtyEight did provide one, though it was incorrect.
- FiveThirtyEight predicted that Republicans would win the Georgia senate seat on Election Day, while we correctly predicted that no canidate would recieve a majority, sending the race to a run-off.
From our Pre-Election final Georgia Projection.
- We predicted that Obama would win 364 electoral votes, while FiveThirtyEight predicted that Obama would win 353 electoral votes. Obama actually won 365 electoral votes.
But because of the winner-take-all system, this is not a good way to gauge accuracy. Instead, it is a better idea to look at how we did at predicting the margins in individual states:
Presidential:
In terms of mean absolute error, my model had a slightly lower mean absolute error than his. But the Kurtosis of his prediction residuals is much higher than mine.
That means that most of the time, his predictions were about as accurate as mine. But when his predictions were off, they were really really off. In his defense though, his model was mostly off in states that were not important(Washington DC, Wyoming, etc.)
But, everyone has their own metrics for this sort of thing, so for those who want to see the raw data, click here.
Senate:
As can be seen, FiveThirtyEight outperformed Stochastic Democracy in the Senate by quite a bit. This gives us something to work on between now and 2010...
Popular Vote:
Stochastic Democracy did quite a bit better than FiveThirtyEight, while Pollster falls in the middle.
Also, since I don't want anyone to go through the tedious process of data collection, raw certified election results by state(Presidential and Senate), are available on a spreadsheet here.
**************Cross-Posted at StochasticDemocracy**********