Tuesday, November 04, 2008

Final Presidental Electoral Vote Simulation Predicts Obama win

It is no surprise that the final presidential electoral vote simulation based on the Intrade Prediction market data predicts a win for the Democrats and the Obama/Biden campaign. It has been trending that way for several weeks. Only 4 simulations out of 1000 show a McCain/Palin victory.

The median electoral vote from the simulations is 351, but the most frequent number is 364 electoral votes for Obama/Biden, which is my official prediction for the race. The table below shows that all of the states, according to the prediction market, have moved to strong Republican or Democratic except for Missouri, which is weakly Democratic at this point.

A plot of the electoral votes from the Intrade data over the past weeks shows that the Democrats have never been below 270 with a straight addition of the states. Though some weakly Democratic states would have left them with a deficit.

The plot of the median electoral votes and the fraction of simulations which resulted in a Democratic victory over the past few weeks shows that the lowest point in recent history was the week of September 16th.

Barring unforeseen circumstances, I think that the Democrats should emerge victorious. You can make that happen by remembering to vote.

Other sites show similar results using polling data:

FiveThirtyEight.com which has Obama at 348.6 electoral votes to McCain's 189.4 and the Democrats winning in 98.9% of his 10,000 simulations.

Electoral-vote.com has 286 electoral votes for Obama, and 225 for McCain with 27 in a tie. This site also uses state by state polling data.

RealClearPolitics.com has Obama with 278 electoral votes and McCain with 132 with 128 in the toss-up category. They use polling data. That is by far the most pessimistic result for the Democrats of these major polling and simulation websites. With no toss ups they have Obama with 338 and McCain with 200.

270towin.com is running very slow today. They use the last 1000 simulations in their visualizer to build up results that have Obama with 342 electoral votes and McCain with 196. They have the Democrats winning in 98.7% of their simulations. They also use probabilities of each state winning based on polling data with some clipping of the data. Even their 90% confidence interval has an Obama/Biden win with their most pessimistic number at 284.

The Truthisall 2008 electoral model has a final prediction with Obama winning by 76-64m votes; 367-171 EV; 53-45% vote share margin. They seem to be real concerned about election fraud and have a hard to understand election model with assignments for undecided voters.

What's your prediction?

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