

Show HN: Predicting the winner of the US Presidential Election - sendos

In 2008, I did some calculations to estimate the probability of Obama or McCain winning the election, using state poll results, and plotted the probabilities vs time, right up to the election. The results were quite interesting.<p>So, this year, I'm doing the same for the 2012 elections, and have put it all up on:<p>http://prespredict.com<p>I include both 2012 and 2008 results, and make an attempt to see how they correlate with campaign events and national news stories. There is also a section where I describe the methodology.<p>Let me know what you think<p>[P.S. I used bootstrap to get the site up and running quickly, but I'm not too pleased with how it looks. Any suggestions or templates I can use to improve the look?]
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pinks
If you're unhappy with the default Bootstrap look, <http://bootswatch.com/>
has nice free themes. It made a world of a difference when I ditched the
default and used one of their themes on a current project.

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impendia
99.7% for Obama in March, and 82.6% now?

According to you, the odds of Obama losing are now higher by a factor of 58.
That is _huge_. What has happened in the last four months that justifies such
an overwhelming shift?

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sendos
> _According to you, the odds of Obama losing are now higher by a factor of
> 58_

Just to be clear, this is not strictly speaking "according to me", that is I
don't use my personal opinion to come up with these numbers. I just take daily
state poll results from electoral-vote.com and pass them through some
equations. No human intervention.

Having said that, I think what was happening in the March timeframe and before
was that the field of Republican potential nominees was very uninspiring to
Republicans, which can be seen by how often we saw a new front-runner, only to
lose their front-runner status and usually bow out shortly thereafter.

So, perhaps, against this amorphous group of uninspiring candidates, Obama
attracted a lot of voters. Then, as the Republicans started settling on one
candidate, and started to slowly accept him as the nominee, he now has a much
better chance against Obama.

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il
If your predictions are so good, why not keep the data to yourself, get on
Intrade, and make a ridiculous amount of money?

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sendos
Even if we assume my predictions are very accurate, I'm not familiar enough
with Intrade to know whether it's mostly guided by fundamentals vs technical
analysis.

That is, Obama's value may go up because many people think it will go up, due
to some technical indicators, and not necessarily because Obama's probability
of winning went up.

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impendia
This doesn't make sense to me.

Indeed, the more irrational you believe Intrade's users to be, the more
incentive you have to use it. Same for the stock market, or any other market.

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sendos
Does this always work? If you think that company X should be valued at $10
billion, but is currently valued at $5 billion because the market is being
irrational, are you claiming that it's _always_ a safe bet to invest in this
company? Are you claiming that in the long term the market becomes rational
and will surely value the company at the value you think it is worth?

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abbasmehdi
You're missing your parent commenter's point. He/she means to say if more
people are wrong then the odds are stacked higher against the candidate you
expect to win therefore the payout in favor of your candidate would be higher.
Sorry I think my comment is even more confusing but I hope you arrive at this
conclusion anyway.

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sendos
Clickable: <http://prespredict.com>

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27182818284
What are the main differences between you and your methods and
FiveThirtyEight?

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sendos
I'm not too sure, since I can't find the exact model used by FiveThirtyEight.
If any of you can point me to a post of theirs where they describe their model
in detail, that would be great.

From the few things I have found out, some differences are that (1) they take
into account correlations between states, which I don't as of now, but plan on
adding and (2) they use Monte Carlo simulations whereas I have a closed-form
expression for calculating the probability.

Beyond the above two differences, I'm not sure what model they use to convert
the poll results into final probability estimates.

FYI, in case you haven't seen it yet, my methodology is described at
<http://prespredict.com/methodology.html>

