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Tonight's election prediction


October 16 2012

I am using Huffpost's numbers for today (pre-debate) for tonight's election prediction. These numbers much more strongly favor Obama than either of the two other numbers I am using. Simon Jackman has an article that explains the model used to make these numbers.

My simulation with Huffpost's numbers

Using a strong random number generator (described in yesterday's blog), I simulated the presidential election 100,000 times. The simulated results for today's Huffpost numbers are as follows:

Chance of winning election
Obama  96.7%
Romney  3.2%
Tie     0.2%

By State

Here are some raw numbers showing how much influence a given state has on the election results. What I have done is look at all of the cases in the model where a given state is won by a given candidate, and compare how winning or losing the states affects their chances of being in the White House next year this time:
Obama gets CO
Romney   1.72988%
Tie      0.10658%
Obama    98.1635%
Romney gets CO
Romney   5.41102%
Tie      0.225566%
Obama    94.3634%

Obama gets FL
Romney   0.00313372%
Obama    99.9969%
Romney gets FL
Romney   4.64833%
Tie      0.224706%
Obama    95.127%

Obama gets NH
Romney   2.34891%
Tie      0.153086%
Obama    97.498%
Romney gets NH
Romney   4.54009%
Tie      0.152856%
Obama    95.3071%

Obama gets NV
Romney   2.49987%
Tie      0.118921%
Obama    97.3812%
Romney gets NV
Romney   5.67856%
Tie      0.281542%
Obama    94.0399%

Obama gets OH
Romney   0.894281%
Tie      0.100098%
Obama    99.0056%
Romney gets OH
Romney   25.8884%
Tie      0.682143%
Obama    73.4294%
The most interesting thing for me is that the model has only one path to victory for Romney if Obama is able to get Florida. I have made a map of Romney's one and only 1-in-100,000 (according to Huffpost) path to victory for Romney without Florida, which can be seen here:
Then again, Huffpost's model says that Obama right now only has a 32% chance of getting Florida (Nate Silver and Nerd Wallet give Obama a slightly higher chance of getting Florida, but they both give Obama a lower chance of winning the election).

A note on the random number generator

The random number generator rolls a 1000-sided dice by grabbing two bytes from RadioGatun[32]'s bitstream. This gives us a number between 0 and 65535; should the number be 65000 or higher, the program discards the roll and tries again.

Once it gets a good roll, it takes the low three digits of the random number to get a number between 0 and 999. For example, if the number is 45,737, the program uses the number "737" for the dice roll. If Obama's chance-in-1000 of getting a state is lower than the roll, Obama gets the state, otherwise Romney gets it. Using the 737 example and Florida, since Obama has a 32% chance at Florida in Huffpost's model, Obama won't get Florida since he needs a 319 or lower to get it.

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