How Many Goals Will Be Scored
The number of goals in a game is influenced by two factors - the relative strength of the teams and the goals records of the teams.
The first, in my opinion, is very much more important than the second. According to my research, it is roughly three times as important. As a general rule, the greater the goal difference between two teams, the greater the goals total. It stands to reason, really.
In spread betting, the difference between the number of goals each team score is called supremacy.
Even if you bet only on fixed-odds, you will still want to know what the goals expectation should be - or, at least, you will if you want to bet on goals totals or correct scores.
Goals expectations are normally at their lowest when supremacy expectations are zero - when two teams are evenly matched and each is as likely to win as the other.
As supremacy expectations go up so, usually, do goals expectations.
Let's imagine a game between two teams we will call City and United. Let's imagine City have an average goal difference per game of +0.5 and United have an average goal difference per game of +0.1.
If they met at a neutral venue - say in a cup final - the supremacy expectation would be 0.4 City/United (0.5 - 0.1 = 0.4).
If they played at a non-neutral venue, the team playing at home would enjoy a slight advantage and the team playing away would suffer from a slight disadvantage. Exactly how much varies from competition to competition and season to season, but you will not go far wrong if you assume that it all adds up to about four-tenths of a goal - certainly, not if the teams are from the Premiership and Football League or one of the top European divisions like La Liga or Serie A.
If City were playing at home to United, therefore, the supremacy expectation would be 0.8 City/United (0.5 - 0.1 + 0.4 = 0.8).
In matches with a supremacy expectation of 0.8, the typical goals expectation is 2.7.
Let's assume, however, that United's games have been unusually high-scoring. We said earlier that they have been scoring an average of 0.1 goals per game more than they concede. Normally, the total number of goals in the games of such a team would average 2.5. Let's assume that goals in United's games have been averaging 3.0 - or 20 per cent more.
When City play at home to United, the goals expectation should be higher than 2.7 - but not 20 per cent higher.
According to my studies, teams who have been involved in high-scoring games in the past tend to carry on being involved in high-scoring games in the future - only, their next games are not as high-scoring as the previous ones. Similarly, teams who have been involved in low-scoring games in the past tend to carry on being involved in low-scoring games in the future - only, their next games are not as low-scoring as the previous ones.
I said before that, when evaluating goals expectations, the relative strength of the teams is three times as important as the goals records of the teams. Or, to put it another way, the second factor has only one quarter of the overall importance.
When City play at home to United, the goals expectation should probably be 2.8, perhaps 2.9 - about five per cent more than 2.7 (because 20 per cent multiplied by a quarter is five per cent).
Actually, it's not quite that simple, but don't worry too much about the complications. What I have given you here is a quick, rough calculation which most of the time will produce a figure that is about right.