Therefore, it is long-term profit that we should all be seeking, and making that long-term profit from your betting is reliant on being rewarded with odds larger than the actual chances of the bet you strike.

Every event, sporting or otherwise, is governed by mathematical probability. It is incumbent upon aspiring successful bettors to have as good an idea of the probability of any event they are betting on as possible. Everybody familiar with betting will have a general awareness of what the odds of an event in any particular sport should be, even if it is often only an unconscious one. With just a little practice, pricing up an event yourself will become second nature and an essential part of your betting armoury. Use our table expressing odds as a probability to help you do this.

Every event, sporting or otherwise, has a mathematical probability. For example, an inspection of the Bettorlogic Form Lab before Bordeaux’s clash with PSG in 2009 would have revealed that Bordeaux were unbeaten at home since October 2007 and had a record of W17-D6-L0 in that spell. PSG for their part were W5-D4-L11 away in 2008, with four of their last five away trips to top-six teams lost. Though only two points separated the two teams before play, Bordeaux had a 74% home win ratio from a large sample while PSG had lost 55% of their away games in 2008, mostly against inferior opponents than Bordeaux.

It would not be an unreasonable assumption to make Bordeaux at least a 55% chance to win this match with 28% the draw and 17% a PSG success,  translating to approximately odds of 1.80, 3.50 and 6.00 respectively. With Bordeaux trading at 2.10+ on Betfair in this match, a clear betting opportunity would present itself. With a little research to check that the price wasn’t too good to be true, ie that Bordeaux had no injury problems or PSG hadn’t signed Lionel Messi and Fernando Torres and re-checking that the Form Lab really did present such positive figures for a home win, a nice weighty bet on Bordeaux could be struck.

It is a matter for the individual concerned how much value, or ‘juice’, they requires before placing a bet. You may decide not to bet until you obtain at least 10% value on top of what you consider the true price. It is certainly true that some matches are far easier to price correctly than others, and so the astute backer may want considerably more juice in certain matches than in other more solid or obvious ones. Remember, one big advantage you have over the bookmaker is that you only need to bet when you decide to while bookmakers must lay in every match.

Anyone pricing up a sporting event should do it before they see any prices for the event in question; it is virtually impossible not to be influenced by other people’s odds. A key element in making odds is to question whether you would lay or bet at any of the odds you have made. If, for instance, you price a Big Four team at 1.10 to beat a bottom-six side at home, the draw and away odds would have to be around 14.0 and 40.0 respectively to add up to a true 100% book.

According to our table converting percent chance to probability, you can see that 1.10 is an expression of a 91% chance of something happening, 14.00 is 7% and 40.0 2.5% (all rounded up to the nearest digit for simplicity).

We know from using the Bettorlogic Form that as of 12 January 2009, Big Four teams had won just 54% of home matches against bottom-six opposition this season, winning seven and drawing six of the 13 games played. That’s a 54% probability that equates to around 1.86! However, it is important to note that each season has different patterns and this season has seen unusually high incidences of shock results against Big Four teams. For example, last season Big Four clubs won 73% of their home games against bottom-six opposition.

In our opinion, coming up with a price of 1.10 for the Big Four home win, 14.00 for the draw and 40.00 for the bottom six win would be time to go back to the drawing board. This season (2008/08) no bottom six side has been so inferior as to warrant such large odds. If a bookmaker offered such a price, he would almost certainly end up with big liabilities on both the draw and away win. In this example, a perceptive backer may combine the draw and win for the bottom-six side, giving odds of about 11.0 for either result. Though it is tempting to feel that the favourite should be very short odds, this discipline will enable the bettor to evaluate the true odds much better.

The perceptive backer may strike a bet of £70 on the draw and £25 on the away win; a total stake of £90 which would return £1000 in total (£980 for the draw due to the approximation of the table) in the event of either a draw or an away win. Seeing that the odds for draw and win are too large, we would go back to the drawing board and possibly return with something like 1.30-5.0-22.0. Practice makes perfect in every field, and a little practice in the art of pricing will soon be rewarded.