Board Game Arena

BGA clearly doesnt care whether players participate in Arena, or it would have a more sensible and inclusive Arena system.

Cile wrote: ↑04 July 2024, 01:32 If you're playing enough to try to compete for a high rank in a season your K factor is going to quickly approach 1 anyway.

You are just making things up. The K factor never changes, it stays at 40 the whole time. Actually a decreasing K factor the more you play could even be reasonable idea. But reality is far from it.

dschingis27 wrote: ↑04 July 2024, 16:08

Cile wrote: ↑04 July 2024, 01:32 If you're playing enough to try to compete for a high rank in a season your K factor is going to quickly approach 1 anyway.

You are just making things up. The K factor never changes, it stays at 40 the whole time. Actually a decreasing K factor the more you play could even be reasonable idea. But reality is far from it.

https://boardgamearena.com/faq

The easiest situation is a 2 player game. You will gain a number of ELO points equal to K x (W - p(D)) where:

W is the result of the game: 1 for a victory, 0 for a defeat, 0.5 for a tie.
D is the difference of ELO between you and your opponent.
p(D) is the probability of victory considering the previous difference (see Wikipedia for details).
K, the 'elasticity factor,' has a value that depends on the number of games you have played: 60 for your first 10 games, 40 between your 11th and 20th games, 20 for your 21st onwards.

Okay, so K doesn't approach 1 because that would result in 0.5 ELO for beating someone with the same ELO as you, but it does go down the more games you play.

Romain672 wrote: ↑04 July 2024, 12:08 I proposed a while ago to use the 'Luck' rating in the k-factor formula. I just checked for Can't stop and Lucky number and it's at 4, so it would work.
And then I proposed to use the 'Interaction' part with 3+ players games to reduces the '% to win' of the highest elo (ie make it so that the highest elo lose less, and lowest win less ; but not less than if they got identical elo). This is because targetting a player is easier on those games (I believe).

Now the problem is how to find the right number? Do you apply it to all ranking?
I think you could.

How many games on BGA? It's not feasible for BGA to define different 'luck' and 'interaction' ratings for every single one of them, and then continuously tweak them as users complain that they are too high or too low. You know how much luck and interaction is in the game you are playing, you can take that into account yourself.

Cile wrote: ↑04 July 2024, 16:29

dschingis27 wrote: ↑04 July 2024, 16:08

Cile wrote: ↑04 July 2024, 01:32 If you're playing enough to try to compete for a high rank in a season your K factor is going to quickly approach 1 anyway.

You are just making things up. The K factor never changes, it stays at 40 the whole time. Actually a decreasing K factor the more you play could even be reasonable idea. But reality is far from it.

https://boardgamearena.com/faq

The easiest situation is a 2 player game. You will gain a number of ELO points equal to K x (W - p(D)) where:

W is the result of the game: 1 for a victory, 0 for a defeat, 0.5 for a tie.
D is the difference of ELO between you and your opponent.
p(D) is the probability of victory considering the previous difference (see Wikipedia for details).
K, the 'elasticity factor,' has a value that depends on the number of games you have played: 60 for your first 10 games, 40 between your 11th and 20th games, 20 for your 21st onwards.

Okay, so K doesn't approach 1 because that would result in 0.5 ELO for beating someone with the same ELO as you, but it does go down the more games you play.

There is not much documentation on BGA thus it is understandable that you mix ELO with EAS. ELO has a decreasing K factor since you start with 0 ELO and you need a high K factor to more quickly reach the true ELO value. High fluctuation of ELO for a beginner is a feature - not a bug.

EAS has a constant K factor of 40 and everybody starts with 1500 EAS. Constant high fluctuation during the whole season esp. for high luck games is a bug - not a feature.

Best way is to ignore Arena ranking in those games, BGA does not bother to change.

Cile wrote: ↑04 July 2024, 16:34

Romain672 wrote: ↑04 July 2024, 12:08 I proposed a while ago to use the 'Luck' rating in the k-factor formula. I just checked for Can't stop and Lucky number and it's at 4, so it would work.
And then I proposed to use the 'Interaction' part with 3+ players games to reduces the '% to win' of the highest elo (ie make it so that the highest elo lose less, and lowest win less ; but not less than if they got identical elo). This is because targetting a player is easier on those games (I believe).

How many games on BGA? It's not feasible for BGA to define different 'luck' and 'interaction' ratings for every single one of them, and then continuously tweak them as users complain that they are too high or too low. You know how much luck and interaction is in the game you are playing, you can take that into account yourself.

https://boardgamearena.com/gamepanel?game=cantstop
=> Game information
=> Luck

It is to have something better, not to have something perfect.

I think those are added by the developper some rare games have 3/3/3/3 which is I believe the default value).

euklid314 wrote: ↑04 July 2024, 17:15 Best way is to ignore Arena ranking in those games, BGA does not bother to change.

Yes, correct. Every once in a while I get drawn into Arena and my competitive mind starts caring. But yeah, the dry truth is what you say.

As the Arena is for a fixed time period I do think it odd that if you win your first 10 games and lose your next 10 you have a mmuch lower ranking than if you lose the first 10 and win the next 10 agaist equal strength opponents. The K Factor effectively determine how big that difference is.

This scoring mechanism can also make it tempting to stop playing when you get high in the rankings.

I think it would be better to have the Arena based on an average score of your games, where you score 0 for a loss and points for a win based on the ELO of your opponent. TheAreana tiers would make sure you have a minimum number of games, you could incentivise players to play more by being able to discard your worst X% of games (rounded down)