Comments on: Prediction market aggregator

By: Chris. F. Masse .COM

Chris. F. Masse .COM — Wed, 27 Sep 2006 09:37:36 +0000

Hi Mike,

When I checked OddsChecker, sometimes ago, they would include BetFair and Betdaq in many comparison charts.

They seem to do it less. I hope that sponsoring/advertising is not a factor.

OddsChecker was the most famous of all the British odds comparators. Maybe some brand-new websites are better, I should investigate further one day.

TradeSports is not included because this betting exchange is not know in the U.K., and floats only American-centric contracts. (Or maybe they don’t pay OddsChecker.)

Thanks for your other remarks,

Chris Masse

By: Mike Linksvayer

Mike Linksvayer — Wed, 27 Sep 2006 03:49:05 +0000

Brad, good catch, I didn’t notice that difference in the contracts, though with an odd number of seats and AFAIK no non-D&R candidates with any chance of winning the chances of the difference being important is very slim.

Chris, yes Oddschecker for non-sports bets is exacly what I want. Hopefully they will expand, I was not aware of them. It looks like there aren’t big differences between exchanges excepting low probability events. Is it just me or does Oddschecker not check Tradesports?

The Wolfers and Zitzewitz paper doesn’t say real money arbitrage is impossible, they just didn’t find siginficant opportunities in a couple datasets, which is exactly what I’d expect. So my question has already been answered.

Now if play money markets allowed trading play money between players they could be linked to real money by third parties just as MMORPG economies are, permitting play money arbitrage.

By: Chris. F. Masse .COM

Chris. F. Masse .COM — Mon, 25 Sep 2006 12:30:23 +0000

So the discrepency between Betfair and TradeSports is due to lack of volume at BetFair.
That’s the difference between the two platforms: TradeSports is all about US topics (football, baseball, basketball, US politics) and BetFair is all about UK topics (British horseracing, soccer, rugby). You’ll find low volumes on TradeSports for British stuff and you will find low volumes on BetFair for American stuff (except US stuff that is broadcast live on international TV, like the SuperBowl). So comparison between the two is only possible when you have sufficient volume in the weakest platform (for that particular topic).

==
Footnote: Contrary to stock markets, futures markets float ‘proprietary’ contracts. Maybe Jason “The Brain” Ruspini could wake up from hibernation and tell us more about implications for the question that Mike posed.

By: Chris. F. Masse .COM

Chris. F. Masse .COM — Mon, 25 Sep 2006 12:22:26 +0000

Wait. The impossibility of arbitrage between real-money prediction markets on US politics has been discussed by many economists’ papers. The one I remember is the Prediction Markets paper:
http://bpp.wharton.upenn.edu/jwolfers/Papers/Predictionmarkets.pdf

As for sports, I have nothing in mind.

By: Chris. F. Masse .COM

Chris. F. Masse .COM — Mon, 25 Sep 2006 12:03:51 +0000

Thanks for pointing to me my mistake (leaving out WSX, which is indeed play money). I corrected.

For your information, there are automatic comparators of bookmaker odds. They also take into account the probabilities generated by prediction exchanges (mainly, BetFair and Betdaq). The best known is:

Oddschecker
http://www.oddschecker.com/

As for your question, I’ll publicize it and we will all mind it.

By: brad winterson

brad winterson — Mon, 25 Sep 2006 08:31:40 +0000

There is a definite ard opportunity between Betfair and Tradesports but the risk is that if the elections end in a 50-50 situation, the markets would be treated differently. BF’s market is on most seats so would settle it as a dead-heat where Tradesports’ market is on GOP retaining control and so would settle the markets at 100. I’m not sure how big this risk is but the size of the arb might be worth it.