I wrote this post because I think the Online Rating system used in DSJ could be improved.
The Elo System is good for 1 on 1 games, but problems occur when there are more players.
The current method is to treat each competition as a series of 1 on 1 duels.
I think this appraoch is unfair, as one unlucky jump may result in losing of 50 "duels".
You would agree, that one bad jump is not the same as 50 bad jumps.
I myself am hosting an online racing competition with Elo-based formula to calculate skill.
To solve the issue with high number of competitiors, I am using Elo adjustment.
First, I calculate the changes in Elo scores of all players, the same as in DSJ Online.
Then, I divide each score by the square root of the number of opponents (this is the adjustment).
so, my proposed formula is new_elo = old_elo + default_difference / sqrt(num_of_jumpers - 1)
To compare both methods I created a graph below.
The graph shows how much points would you gain by beating X equal opponents (let's say you all have 1000 points).
DSJ Online uses the K-value of 1 in the Elo formula, I increased it to 6, to accomodate the adjustment.
Findings:
1. In a game of two equal jumpers, you would only gain 0,5 points with default method, 3 points with adjustment. Imagine jumping 1 on 1 with a friend. It would take ages to build up an advantage with the default method.
2. In case of 36 opponents, both methods yield the same results (beating 36 equally ranked opponents gives you +18 points).
3. In case of 64 equal opponents, you gain 32 points with default method, only 24 with adjusted. Imagine having a terrible qualifying jump, with a fall perhaps. Last place and many points lost. The adjustment fixes this.
Well, this is it. Let me know what you think. As I've said, I'm using this formula in my racing league and it works well.
