# Thread: Calculating probability in football mathes

1. ## Calculating probability in football mathes

I am wondering how the bookmakers calculate the odds about football matches. There is no chance that they do that on hand, because the games are simply too much. So there must be some sort of mathematical algorithm. Therefore, having in mind that bookmakers have all the football statistics, how do they do it? I have recently come across a very interesting website called Футболът е математика, футболни прогнози за всеки кръг чрез алгоритъм. , which gives football predictions based on mathematical statistics. Unfortunately, they did not reveal me their algorithm. So, can anyone help me ?

2. ## Re: Calculating probability in football mathes

Originally Posted by SmartyOneAsHell
I am wondering how the bookmakers calculate the odds about football matches. There is no chance that they do that on hand, because the games are simply too much. So there must be some sort of mathematical algorithm. Therefore, having in mind that bookmakers have all the football statistics, how do they do it? I have recently come across a very interesting website called Футболът е математика, футболни прогнози за всеки кръг чрез алгоритъм. , which gives football predictions based on mathematical statistics. Unfortunately, they did not reveal me their algorithm. So, can anyone help me ?
I thought they did it based on the bets received, adjusting the offered prices so that they were guaranteed to make a profit (at least partially).

You can deduce for yourself that there is little predictive power in the models used for published predictions since otherwise the developers would be using the predictions themselves to make a killing. In fact publishing a prediction is a guaranteed way to get the prices offered by the bookies to change in a predictable way thus gaining a margin for betting against your own predictions (it works with stock market forecasting, though there the prices change in the other direction...).

Anyway if you are still interested try googling football result prediction algorithms - Google Search

CB

3. ## Re: Calculating probability in football mathes

Bookmakers do use mathematic modelling to some degree. Poisson distribution, is a good base to start from, although this is renowned for underestimating the probability of a draw and other low scorelines. The diagonally inflated bivariate model (which brings me to this forum as I'm currently trying to understand this method), inflates the probability of 0-0 and other draws, e.g.,

p is a number between 0 and 1
f_d is a number which describes how the goal dependence (for a draw) depends upon the score (i.e. when X=Y) - this is the 'diagonal inflation'.

Lambda1 and Lambda2 are the respective team's goal expectancy.

Lambda3 is the covariance of Lambda1 and Lambda2, to some degree, but not completely, which confuses me!

When the above is worked out for each scoreline, you then add the probabilities together where Team A wins, e.g,.

1-0, 2-0, 3-0, 4-0, 5-0, 2-1, 3-2, 3-1, 4-3, 4-2, 4-1, 5-4, 5-3, 5-2, 5-1. This will give the probability of Team A winning.

You then do the same for the Draw (add the draw scorelines) and Team B (add Team B's winning scorelines). Once you have the probability, you can then convert it into odds. If the bookmaker or betting exchange is offering odds above the probability / odds of the game that you worked out, then you have what is called a value bet. This is one way to beat the bookmakers, constantly finding value where the bookmaker has over-priced a fixture, is a proven method of long term winning.

If anyone can offer me any help in working through the above example, as I'm only half way there, I would be very grateful. In return, I can provide maths papers on the subject.

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### goal expectancy calculator

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