Board Game Arena

I'm trying to figure out how the elo system of BGA works. I read this BGA wiki page: http://it.doc.boardgamearena.com/Rating. I can't understand which is the value of "K" in the last formula ( Rn = K.P + (1-K).Rp). Can you help me, please? Thanks!

That formula isn't accurate, so you can just ignore it. I'm not sure if it was ever used, but definitely isn't how Elo is calculated these days.


For a 2 player game the basic formula is: K/(1+10^((Ra-Rb)/400))
For more than 2 players, a single game is treated as a series of head to head matchups. The multiplier is adjusted downwards slightly, but I don't know exactly what it is. I think with 3 players K is 75-80% of the 2 player value and for 4 player is 60-67%

K is as follows:
If you have less than 10 games played, K=60 (you win 30 points against a player with the same ELO).
If you have between 10 and 20 games played, K=40 (you win 20 points against a player with the same ELO).
Above 20 games played, K=20 (you win 10 points against a player with the same ELO).

Allright, thank you. There was something that didn't make sense to me, in fact.

I'm confident with the ELO system 1vs1, but I don't know how it works with more player. Can you just tell me in a simple way which passages and formulas should I use in addition to the basic ones of the classic ELO system? Thank you!

demiurgsage wrote:

demiurgsage wrote: if a game is played with more than two players then every result will be multiplied by N/(2 * (N-1)), N - number of players if N is equal or less than recommended number of players. if N is more than recommended number, the multiplication factor is (recommeded N)/(2 * (N-1))

Thanks!

So assuming recommended N is equal or greater...
N = 3, => 75%
N = 4, => 67%