Board Game Arena

What is the formula by with BGA calculates how many "game evolution" points to award/subtract from the winner/loser total at the end of a Duel game? Its a bit weird. Sometimes I win by victory points and I am awarded +13 evolution points. Other times I win by victory points and I am only awarded +5 evolution points. What gives?

You are referring to ELO which is based on the level of the two players and has no bearing on the method or margin of victory

Two players with a similar ELO would be expected to win roughly 50% of the games together as they are deemed to have similar relative skill levels so the increase / decrease for a game would be small

At the end of the game, the winner is essentially taking points off the losing player based on their relative likelihood of winning

A game between a player with a high ELO and a low ELO would expect the higher rates player to win a much higher % of the time. Therefore, if he wins the reward would be lower.

However, if the lower rates player wins that would be more against the odds and they would be deemed to have beaten a higher skilled player, so the rise for this player (and fall for the opponent) would be higher

I would recommend searching 'ELO ratings' which is commonly used in games like Chess if you want to learn more

https://www.omnicalculator.com/sports/elo if you want to check something specific.

also understood recently how it works in a nutshell (besides the formula you could copy paste in excel... ):

for starters there is a K-factor which decides how much elo you can lose/win this game at a maximum (first 10 games it's 60, game 11-21 it's 40, than it's 20 from there) - the K-factor is for an individual player here, not same for all ...

after a win you get (1-ProbabilityOfWin)*K-factor elo.

your ProbabilityOfWin is based on your elo and that of your opponents.
here a little list if you are x elo ahead:
70 elo -> 1.5 times more likely to win than your opponent -> 1.5/(1+1.5) = 0.6 [your ProbabilityOfWin] {assuming K-factor=20 you get 0.4*20 = 8 elo}
120 -> 2.0 -> 2/3 ProbabilityOfWin
190 -> 3.0 -> 0.75 ProbabilityOfWin
240 -> 4.0 -> 0.8 ProbabilityOfWin

basically you can use this steps to quickly guess what a given elo difference means - if you add one of elo values, you multiply the associated "more likeliness that you win, compared to your opponent" ... it's actually really cool
Edit: obv. expample difference of 430 elo -> 430= 240+120+70 => 4*3*1.5=18 [times more likely to win than your opponent]; in other words in 18 of 19 times you should win and 1 of 19 times your opponent should win, purely based on elo.


PS: hope I didn't mess up some values, and explained clearly enough, since I didn't really have time to do it better for now^^