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I've been wondering about this for week. Is there a statistical smoking gun anywhere?

by pg 14y ago

jsdalton 14y ago
One could look at the state-by-state markets in the weeks leading up and see if the probability predicted differed greatly from the main market. It would be far trickier to manipulate the markets state by state in such a way that their probable outcomes aligned with the probable outcome of the national markets. I just looked at the InTrade state numbers from 11/2 (which I have on a spreadsheet) and running a few dozen simulations I was getting Obama winning about 80%. That's a pretty significant difference from where the national numbers were on 11/2 (I think about 66% maybe?) Of course, if they differ it might just be because the Intrade market is imperfect, in which case it would represent a nice arbitrage strategy for the next election...
andrewcooke 14y ago
there's http://www.washingtonpost.com/blogs/ezra-klein/wp/2012/10/23/how-to-manipulate-prediction-markets-and-boost-mitt-romneys-fortunes/ http://www.washingtonpost.com/blogs/ezra-klein/wp/2012/10/23... which was mentioned at http://fivethirtyeight.blogs.nytimes.com/2012/10/24/oct-23-the-virtues-and-vices-of-election-prediction-markets/ http://fivethirtyeight.blogs.nytimes.com/2012/10/24/oct-23-t... chart in first link shows large romney buyer. not sure if that's what you're looking for with "statistical smoking gun" though. a little more analysis at second link.
sire404 14y ago
No it's most likely just overconfidence in the market by a few individuals. Intrade actually checked for manipulation themselves: "We checked this out for potential manipulation - it certainly fit the pattern at first glance. However, during the period you reference above 40 individuals bought Romney shares and no individual bought more than 15% of the shares traded during that period. A look at those 40 accounts shows nothing suspicious. So we don't believe this was manipulation but more a run on Romney when the market was unusually thin." http://www.theatlantic.com/business/archive/2012/10/should-presidential-campaigns-spend-more-money-manipulating-intrade/264000/#comment-690223587 http://www.theatlantic.com/business/archive/2012/10/should-p... However, even without this spike the Intrade market was misaligned for more than 24 hours. A few of our arbitrage customers made huge amounts of money (outside our software) trading 5-10% arbs between Intrade and Matchbook. This is extremely uncommon. Disclaimer: I'm one of the developers behind sports arbitrage software RebelBetting (http://www.rebelbetting.com http://www.rebelbetting.com)

I've been wondering about this for week. Is there a statistical smoking gun anywhere?

by pg 14y ago

I've been wondering about this for week. Is there a statistical smoking gun anywhere?

One could look at the state-by-state markets in the weeks leading up and see if the probability predicted differed greatly from the main market. It would be far trickier to manipulate the markets state by state in such a way that their probable outcomes aligned with the probable outcome of the national markets. I just looked at the InTrade state numbers from 11/2 (which I have on a spreadsheet) and running a few dozen simulations I was getting Obama winning about 80%. That's a pretty significant difference from where the national numbers were on 11/2 (I think about 66% maybe?) Of course, if they differ it might just be because the Intrade market is imperfect, in which case it would represent a nice arbitrage strategy for the next election...

andrewcooke 14y ago

there's http://www.washingtonpost.com/blogs/ezra-klein/wp/2012/10/23/how-to-manipulate-prediction-markets-and-boost-mitt-romneys-fortunes/ http://www.washingtonpost.com/blogs/ezra-klein/wp/2012/10/23... which was mentioned at http://fivethirtyeight.blogs.nytimes.com/2012/10/24/oct-23-the-virtues-and-vices-of-election-prediction-markets/ http://fivethirtyeight.blogs.nytimes.com/2012/10/24/oct-23-t... chart in first link shows large romney buyer. not sure if that's what you're looking for with "statistical smoking gun" though. a little more analysis at second link.

sire404 14y ago

No it's most likely just overconfidence in the market by a few individuals. Intrade actually checked for manipulation themselves: "We checked this out for potential manipulation - it certainly fit the pattern at first glance. However, during the period you reference above 40 individuals bought Romney shares and no individual bought more than 15% of the shares traded during that period. A look at those 40 accounts shows nothing suspicious. So we don't believe this was manipulation but more a run on Romney when the market was unusually thin." http://www.theatlantic.com/business/archive/2012/10/should-presidential-campaigns-spend-more-money-manipulating-intrade/264000/#comment-690223587 http://www.theatlantic.com/business/archive/2012/10/should-p... However, even without this spike the Intrade market was misaligned for more than 24 hours. A few of our arbitrage customers made huge amounts of money (outside our software) trading 5-10% arbs between Intrade and Matchbook. This is extremely uncommon. Disclaimer: I'm one of the developers behind sports arbitrage software RebelBetting (http://www.rebelbetting.com http://www.rebelbetting.com)