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Around the question if the betting markets are likely to be politically biased, this is highly unlikely. Many years ago you could make money by, for example, betting against England when betting with a English bookmaker (and then potentially arb it by laying off with a Swedish bookmaker) however the betting markets are so transparent and so many bettors use bots that systematic bias doesn't really occur (or if it does it is fleeting).
The Hubdub presidential market has been consistently about 5% more in favor of Obama than the betting markets. We believe part of the reason for this is the automated market maker we use but we are still investigating. We believe it isn't because of emotion based trades (as someone suggested above). The price the market settles on is mostly controlled by our heavy traders. These users spend up to several hours a day on the site competing with friends and trying to climb the leaderboards. They tend to treat their trades as they would real money. The emotion based trades cause volatility but shouldn't set the long term price.
I've done research on prediction markets, and if constructed correctly are really quite accurate. The important thing to remember is that just because a contract is above 50% doesn't mean it's going to happen, and I've blogged about that here:
http://blog.mercury-rac.com/2008/01/25/how-to-i...
What I find interesting is that the best polling stats site, run by a well-known sabermetrics figure (Nate Silver), has a winning percentage for Obama that seems to be tracking well with the prediction markets at around 55-65%. MUCH more data on that here:
http://www.fivethirtyeight.com
And I also enjoy Hubdub... it's a well-implemented prediction market with a good community.
Jed
I think it really comes down to the fact that the polls are overall popularity contests, whereas the markets take into account relative popularity in key swing states. Just because they're getting closer together in national polls, doesn't change the poll numbers out of states like Ohio, Pennsylvania, Florida, etc. I think a large part of the disparity comes out of our electoral system.
Markets are definitely better predictors than polls. There's a great research paper out of the University of Iowa which runs the Iowa Electronic Markets as a research into prediction markets. The abstract of their findings is here:
http://www.biz.uiowa.edu/iem/research/LongRunAc...
"The market is closer to the eventual outcome 74% of the time. Further, the market significantly outperforms the polls in every election when forecasting more than 100 days in advance."
The markets are probably discounting any predictable changes in the polls. If we all know that McCain will get a boost from the convention, who is going to sell us those underpriced McCain contracts to take advantage of this? And the odds are presumably less tight than the polls because there is only a 40% chance that McCain can overcome a three point gap in the vote. The best model is probably to look at the vote gap, and the margin of error for the polls -- that should give you the probabilities of all outcomes (e.g 45-55, 46-54, etc. ) from which the final odds can be calculated.
I would argue that a three point lead in voter polling SHOULD lead to a 60-40 lead in wagering because with a three point polling lead you are statistically favored to win 60% of the time.
I'd assume that if the polling was coming in at 55-40, the wagering odds would be around 95-5.
So obvious it makes me feel stupid actually
BTW, Andy -- a three point lead by itself doesn't mean much, you need to know confidence intervals to turn that into probabilities.
Polls ask the question, "Who will you vote for" whereas the markets ask the question "Who will get more votes overall"
Too bad on the Romney call.
Of course, people trade emotionally in real-money markets as well. Do we think the InTrade community slants Democrat or Republican? I personally suspect there's at least a few percentage points of wishful thinking in the InTrade numbers, and a lot of the trades are of the 'let's bet on my favorite sports team for fun' variety instead of the 'okay, let's rationally make some money' variety.
Prediction markets respond to sentiment in the same way that stock markets do. If external data is saying the company isn't performing well then the price will drop. Last September, John McCain was the about the only one on the Straight Talk Express. He worked his way back and his price rose with it.
Maybe McCain isn't as lame as I originally suspected...
VP
dems define "ready" and "experienced"... Brilliant trap
an inspiring feminist story for
women, moms and fathers of daughters.
the king and queen
She has not
Of course, she isn't on the top of the ticket.
of the day
http://www.avc.com/a_vc/2008/08/comment-of-the....
Read the top post by a dispassionate British observer: http://politicalbetting.com/index.php/archives/...
I personally am amazed that Obama is trading as low as 60%.
It doesn't matter how many supporters you have, it's how many get to the voting booth (and how many of those votes are counted but that's another story).
Booyah
Intrade Real Time Quotes 48% McCain - 53% Obama
That is a big swing amongst the betting folks out there.
http://whatreallyhappened.com/WRHARTICLES/2004v...
http://liesofbush.com/2000election.shtml
blackboxvoting.org is a great site to get active.
"Those who cast the votes decide nothing, those who count the votes decide everything." - Joseph Stalin
http://www.engadget.com/2006/09/06/diebold-voti...
it's worth noting there was also a lot of controversy surrounding the 2008 new hampshire primary on both the rethuglican and dumbocrat side, with evidence suggesting both obama and ron paul were robbed of votes. there are plenty of people arguing both sides of the issue, so it is tough to prove with certainty. below is a google serp that may help people make their own opinion.
http://www.google.com/search?q=new+hampshire+20...
ultimately the diebold issue is very real. so i don't know for sure but it certainly seems possible if not likely that there were issues with the 2006 congressional election as well.