Friday, Aug. 29, 2014

Goals Supremacy Rating

How do we know when a bet is value? The only way we know, is if we have something to measure it against. What we do is measure it against a ratings system and then quantify the result into odds. We can then see what the bookmakers odds are and if they are bigger than our calculated odds, then you have a value bet.

There are hundreds of different rating systems that you can use but one very simple and effective system is known as the Goals Supremacy Rating. This Ratings system is for use on League games but can be used for any country to give a good indication of what the fair odds should be for any league game.

The system is based on the last 6 league games that each team has played, so for this reason you are unable to use it during early part of each season. You are only able to use this system after 6 games have been played by the teams. After the first 6 games you can use it at any time.

What you do is take each team in turn and total up the goals they have scored and then the goals they have conceded in their last 6 league games. So let’s say Team A have scored 9 but have conceded 6, we then do a simple subtraction (Goals scored - Goals conceded) so in our case it would be 9 - 6 = 3. So the rating for Team A would be 3. Now we have Team B, who scored 6 but conceded 10, so their rating would be 6 - 10 = -4.

We now have 2 teams, A and B with ratings of 3 and -4 respectively. Suppose they were going to play each other in the next game, Team A are at home and Team B away. To get an overall match rating for this game we do another simple subtraction (Home team rating - Away team rating) so in our case this would be 3 - (-4) = 7. From this you will see that a positive rating means the home side is stronger, if it is a negative rating, the away side is the stronger team. For our match then we have a match rating of 7 but how does this help us?

With a match rating of 7, we check this rating against the league statistics which show us what percentage of games have been won by the home team and away team when there has been a match rating of 7. You can find the full list at http://www.football-data.co.uk/ratings.pdf .

A match rating of 7 gives us 56.6% Home wins, 23.5% Draws and 19.9% Away wins. To get the fair odds of a home win all you have to do is 100/56.6 = 1.77. So the fair odds of a home win with a match rating of 7 would be 1.77. If you can find a bookmaker offering odds of 1.8 (4/5) or better, then you have a value bet.

I used this particular system at the weekend for the Wolves v Bolton game. Wolves had a rating of -8 and Bolton were -10. The match rating therefore was -8 - (-10) = 2. When you check the Goals Supremacy stats table for a match rating of 2 it gives 49.5% Home win, so the fair odds for a home win (Wolves win) would be 100/49.5 = 2.02. At the time you could actually get Wolves at 2.4, so you had a very good value bet and it was even better when they won.

This then is a very simple ratings system that is easily worked out and you can quickly update the ratings of each team after the weekend games ready for the next time they play. It is a system that works, it costs nothing and it is easily maintained. It finds value bets for you and if you continually find value bets, then you will win in the long run.