The Average Opposition Index relates only to those competitions where there are consistent rankings in place. So with that in mind, it can be applied to any League structure, and also to International games where every team has a FIFA League ranking.
As much as I’d like to be able to take into account Champions and Europa League matches, the teams are competing on a knock out basis aside from the group stages which are too small to apply an average to.
Average opponent scored against is worked out by multiplying the position of the opponent scored against by the number of goals. This is then repeated for all goals, and the total is then divided by the number of total goals.
So Rooney for example (first 9 goals 2011-12 season):
Opponent Rank No. of Goals Rank X Goals
West Brom 11th 1 11
Spurs 16th 1 16
Arsenal 14th 3 42
Bolton 10th 3 30
Chelsea 3rd 1 3
Total 9 102
So 102 divided by 9 is 11.33. This is the average ranking of the opposition per goal for Rooney. To validate this, you can perform a normal average to check:
In the opening round of the season, the teams have no ranking. With that in mind, their final positions from the prior season are taken used, with the promoted teams taking the below:
- Champions = 18th
- Second Automatic Spot = 19th
- Play Off Winners = 20th
The opposition ranking takes the League Position of each team at the start of the round of fixtures. So if the Saturday results mean that the Sunday rankings are available, this will be ignored. If it’s weekend fixtures, then it will be based on the table before any games have kicked off.
The same calculation will be performed at the end of the season and for historical comparisons based on the Final Standings of each team, rather than the position at the time of playing.
Goals per Range:
Whereas the Average Opposition measurement may contain anomalies, another way to track the Big Game Players or Flat Track Bullies is to group their goals into ranges of difficulty.
In most leagues, and certainly the Premier League this season, the Top 6 teams are all a cut above the rest of the league. Similarly, you’ll generally find around 6 teams battling against the drop each season. With that in mind the following groupings have been applied:
Top 6: 1st-6th
Mid 8: 7th-14th
Bottom 6: 15th-20th
Based on these ranges, you’d expect the big game players to have more in the Top 6 category, with the Flat Track Bullies normally wracking them up against the Bottom 6 range.
Goals as Points:
It’s not an exact science, but if you take out the goals scored by each player, you can calculate the amount of points that the goals have been worth. For example, if a player scores in a 1-0 win, then his goal has been worth 2 points as the team would have drawn without it (worth 1 point)
The above table gives further examples of the points won by goals. An interesting one is that 2 goals in a 3 goal win means the player will be responsible for no points in that game. This is sometimes harsh as the player may have scored his team’s first 2 goals, with the 3rd and 4th scored late on when the opposition chase an equaliser.
What this parameter doesn’t take into account is the order of the goal. As mentioned in a Premier League update, “you could for example take Chelsea’s 3-1 win over Norwich last season. As Chelsea won by two goals and had three different goal scorers, take one of Bosingwa’s, Lampard’s or Mata’s goals away and the result would still be 2-1 to Chelsea – meaning that there is no direct impact to the result and number of points. In reality – the opening goal of a game is always important (Bosingwa), and Frank Lampard’s goal in that match was in the 84th minute, which put Chelsea back ahead. Both were important goals, but due to Mata’s injury time goal – the importance in this formula lessens.”