Team Rating (Competitive League)
For several seasons now we have used a somewhat unorthodox method of matching teams for games. The system used is similar to the Elo rating for soccer
. At the beginning of the season we assign a rating number to each team. After each game we will recalculate the new rating number using a formula similar to the one described in the Elo soccer webpage. If a team wins against a team with a higher rating its own rating will improve a lot, winning against a team with a lower rating has less of an effect. Similarly, losing against a team with a lower rating will lower a teams rating a lot, while losing against a team with a higher rating will have little effect.
The effect of this system is that stronger teams will move up in the rankings, while weaker teams will move down. Even if a team is initially ranked incorrectly withing two or three games it will be playing other teams that are of a similar strength, independent of the age group. We will however always take the age group into account too, especially for the younger teams so as to avoid games between teams that are physically too different.
Beginning of the season
At the beginning of the season each team gets a rating number that is the sum of four numbers:
- Age group, (about 400pts per year up to U11, then 300pts per year)
- Outdoor playing league (0 for rec, about 100 per metal, with 500 for Gold, or equivalent)
- outdoor position (100 for first place, 50 for 5th place, 0 for 10th place or below)
- secret league factor (used especially for teams that did not play outdoor to rate them at the correct level)
Rating of games
We use a formula that is very similar to the one used by the soccer elo rating
system. We cap the G (goal factor) at 2, so the goal differences of more than 5 goals do not change the outcome, the weight of games is set at 50. We do not add a home field advantage.
Games are rated once a week, so if you have two games on a weekend the same initial rating number is used to calculate the rating value changes, the changes are then summed up and added to your rating number at the end of the weekend. The table below shows the scoring sheet for one team (those are visible on each teams webpage). The "Points" column shows how many points are awarded or lost for each game, the "[Rating]" shows the rating number at the end of each weekend. The number in square brackets after the team name shows the rating number used to rate this game.
|Sat. Dec. 4, 2010||2:45pm|| Black Dragons ||Fire ||5 - 1|| / ||+68 ||=3714|
|Sun. Dec. 5, 2010||3:55pm|| Black Dragons ||Vipers ||7 - 3|| / ||+46 |
| Sat. Dec. 11, 2010||6:15pm||Sharks || Black Dragons ||5 - 3|| / ||-38 ||=3682|
- The points awarded fo rthe second game are lower than for the first game in this example, beause the first win was against a team with a higher rating
- Note that rating numbers can change if a team has played a game before that has not yet been scored. We try to minimize this effect by upgrading the rating number once a week instead of after every game.