How to identify value in your bets? That’s the big question. My friend, Alex Napier who operates the Best Bet Soccer website, has asked me to write this article to explain how bookmakers’ percentages are calculated and how they provide a guide to assessment of value in the odds on offer. He has asked me to look at soccer betting, where, due to the few possible outcomes (three choices – win, lose or draw) the odds offered are short in any event.

What I’ll show you is:

1. how to calculate the bookmakers percentages;
2. what these percentages tell us;
3. how to assess value in the odds;
4. how to allocate your stake.

How to calculate the bookmakers’ percentages

The following data are taken from a Europa League qualifying match in July 2009 between Bangor City v Honka. The two bookers selected are the two that offered the best price for the draw outcome.

Bookmaker 1

· Home win 4/1 – 20.00%;

· Draw 11/4 – 26.67%;

· Away win 8/15 – 65.22%;

· Total – 111.89%.

Bookmaker 2

· Home win 11/4 – 26.67%;

· Draw 11/4 – 26.67%;

· Away win 8/11 – 57.89%;

· Total – 111.23%

Best odds

· Home win 4/1 – 20.00%;

· Draw 11/4 – 26.67%;

· Away win 8/11 – 57.89%;

· Total – 111.89%

To calculate the percentages divide 100 by the odds on offer plus one. Where the odds are A/B: 100/((A+B)/B). For example, 4/1 is 100/((4+1)/1) or 20.00%. For 11/ 4 consider 100/((11+4)/4) or 26.67%. For 5 – 2 what would the percentage be? 100/((5+2)/2)=28.57%.

What these percentages tell us

A perfectly “balanced book” where the odds offered exactly reflect the chance of each team winning or the draw would produce a total of 100.00%. Theoretically the bookmaker will profit by the total percentage on the match less 100.00%. In the above table bookmaker 1 should profit by 11.89% of turnover on the match and bookmaker 2 by 11.23%. At first sight there doesn’t seem to be much between them but when we compare the theoretical profit of each the margin on the bookmaker 1 odds (i.e. 111.89 – 100.00 = 11.89%) is 5.84% higher than the 11.23% margin on bookmaker 2 odds! Where the odds on offer produce a theoretical profit for the bookmaker the book is said to be “link togel“. The bookmaker 1 book is over round by 11.89% on the away win and bookmaker 2 the home win. Can you calculate when the over round will end? Lets use the following example to complete the calculation.

(1/4100) – (1/4 losses) = 4.84 + 11.23 = 11.84 – 36 = 11.83%

The theoretical profit of the bookmaker 1 over round % is 11.83%. Where the bookmaker 2 over round % is 11.23%

Using the residence rule the theoretical profit of the bookmaker 2 over round % is 11.23%. saving the bookmaker 1 £4.83 for the matched bet.

How often you can expect to make a loss of £4.83 with the residence rule? The answer is 65.22% or 2.02% of your stake.