Dear community,
there is a discussion going on right now concerning revamping / overhauling the current ranking system.
While the current system is doing okay and we could certainly just leave it as is, there are some issues with it. How severe are they? I guess that’s up to personal opinion. For me they are major flaws.
I have listed these in another post, over in the league general discussion thread:
https://www.axisandallies.org/forums/post/1664594
Please also have a look at this post:
https://www.axisandallies.org/forums/post/1664652
Now I have been working these past few weeks on an improved system and I’d like to introduce it to you.
The spreadsheet is here. I hope it’s easy to understand, but explanation will follow.
https://docs.google.com/spreadsheets/d/e/2PACX-1vTfxxzz_KifSSJTAXSIAUUXGiVEFnzOakleCGT7ho8YpjsqaOqpPswl7LxXhe8vRDHBC0lwElQusU3q/pubhtml
Short and simple version for everyone:
Every player starts at a base rating of 1500.
Wins award points while losses give negative points.
Winning against higher ranked opponents give more points than winning against lower ranked ones.
Accordingly, losses against low ranked opponents reduce ELO rating more thank losing against better players.
That’s basically all you need to know: The higher your ELO rating, the better you are!
Tier levels are included but just serve as a visual cue or a motivation. They don’t have any impact on the ranking.
For everyone interested: Now some more details:
Whenever a game is posted, the Ratings of both Players A and B will change.
The exact formula is:
RAnew = Rating of Player A after the game
RAold = Rating of Player A before the game
K = Factor that increases / decreases the points - more on that later
S = 1 if Player A has won, 0 if Player A has lost
EA = Expected outcome for Player A
What is EA?
Now this might look complicated to some. But what this formula does is easy:
The higher the difference between Ratings of Player A and B before the game, the smaller the absolute value of Ea. Therefore a win against much lower ranked players is not worth a lot, while winning against similar or even higher ranked players is worth a lot more.
For losses the opposite is true.
A win by the current #1 against the current last place will award only meager 4 points for the winner and -2 for the loser.
However, the last player would receive a whopping 136 for a win and #1 would suffer -87 for that loss!
Now the Factor F is important: I set it to 500.
This means, that a player with an Elo rating 500 higher than the opponent is 10x as likely to win the game.
Increasing this factor would lead to a wider field of ELO Ratings, while lowering the factor would squeeze everyone closer together.
I found 500 to be quite suitable for our needs but this might change in the future with more games coming in.
Now the other important thing: The K factor.
This factor is quite high in the first couple of games and then diminishes gradually. This is so a player can rapidly find her or his correct place in the ranking system. A very strong player would not need to play dozens of games to climb to the top - the system would realize the strength very quickly and move that player to the top in just a few games. Same of course for not-so-good players.
The exact numbers are up for debate, but I have for now settled on these values:
We can change these numbers if people think the impact of the first couple of games is too high or too low.
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Advantages of this system:
Besides solving the issues I mentioned in my other post, there are the following upsides:
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Transparency
Everybody can always see the amount of points a result gave at any time.
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Climbing is always possible
ELO is not set in stone. Climbing or falling can always be done: The more drastic the change in skill, the faster the ELO change will be.
PPG on the other hand was getting more stable with each more game finished.
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ELO reflects the CURRENT strength
You can see how strong every player RIGHT NOW is and not how strong the year on average was.
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No games are discouraged
No strategic avoiding of games / players anymore!
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No theoretical end, improvement is always possible
PPG always has a maximum. You can reach that maximum with your first game! You might need to complete the necessary amount of games to qualify for playoffs but if you go 3-0 against highest Tier, there is no way to get higher than that.
ELO can always be improved, there is no limit!
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Filtering
You can filter the results quickly. If you want to know how a specific player is doing with the Axis, you can find out!
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Now this is a work in progress. I will gladly take your feedback and discuss it with the community. The goal is to find a system that the majority is happy with!
Some things are TODO at the moment and I hope I will get to it asap.
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ELO Decay
I am planning to implement a decay, if someone is inactive. My idea is that only ratings above the starting Rating of 1500 will decay. The decay could start after 6 months inactivity and then the ELO could drop by 10% per month until it reaches 1500. Please give some feedback!
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Two different rankings
I am in favour of a lifetime ranking. However, most of us love the yearly playoffs and we need some kind of requirements to qualify for them. So my idea is to have two columns: One for the lifetime ELO and one that only uses the results of the current year. That way we can see overall ranking and yearly ranking at the same time. We could keep the requirement of 3 completed games in the current year to qualify for playoffs.
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Factor in bids?
One idea came up by @mr_stucifer to factor in the bids into the results.
For example: For every point the bid is above the average bid, the ELO-change could be 5% bigger than usual (and vice versa). I would need to work out the exact numbers. But I’m not sure if that’s even desirable in the first place? Your feedback is appreciated!
