Upon request, I'll talk a little about arbing in sports. Sports arbitraging occurs when two different bookmakers offering prices on an event with only two possible outcomes and there is enough of a difference in their prices such that you can back both outcomes and make a profit whoever wins. It's very similar to sports trading but the difference is that for arbitrage you are betting almost simultaneously with two books offering different prices. Arbitraging is sometimes described as risk-free betting, this is true in theory, but not in practice.

Let's see a real life example based on the forthcoming 2007 Greek Elections... 

Once upon a time I trusted mathematics. I really did. Nowadays I am full of doubts. I had heard of stories where the betting strategy failed to perform in the same way and started a big losing run forcing the bettor to quit it. I kept wondering how that was ever possible. I don't any more. Here's why:

I started my betting system as you know last September. I recorded the bets and my stats for 2 months, made some tweaks, applied some filters and criteria and voila, I had a most promising method. Then I started funding it and saw my P&L climb. That was nice, an additional source of income which didn't need any major effort, just to update the database. Still I didn't have the time so I gave it to my father who had just retired and had plenty of free time. He soon became a huge fan of this new development and carried his laptop wherever he was and betting 24 hours a day! He never missed a game even during the night, wagering on some Mexican and South American games! I was checking my balance in Betfair in the morning only to see some big winnings on some totally unknown for me teams! The bets were made according to the plan, if the data was there then a bet was on its way. Things were getting well, not thrilling but it was a healthy profit.

Then came the summer...

Sports betting was victorious yesterday, something not so exciting since there was only one football game I was interested in. Cambridge U. won Farsley C. 5-1 and I pocketed EUR220. That is not all the truth however, since my main bet was in the match odds market and the Under/Over bet was a recreational one as usual. Still I don't complain about the result.

It was about time I had a good day in sports betting. Although my strategy is struggling at the moment and needs more days like this, I can't be unsatisfied by the total profit, considering I have lowered my bets. A most welcome day and I hope it is the start of a big comeback.

Here is the breakdown of the P&L... 

Lately my sports betting strategy has encountered a bad drawdown and has lost more than 20% of the profits. While it still remains profitable, that drawdown has aroused some concerns and needs to be re-evaluated. Let's see some interesting statistics:

• Flat betting plan applied: EUR500 fixed stake
• Total turnover: EUR2,587,000
  
• ROI (yield): 2.98%
• Total Bets: 5,174
  
• Database's games: 8,650
  

The sample is quite large for trustworthy conclusions and here are some more useful calculations (read how to do them yourself here):

• Average (mean): 15.69
• Standard Deviation: 533.44
• Confidence (95% significance level): 14.92

 

Things do look a bit rough at the moment but...