Expected winrates based on Glicko2 ratings

[gennan]

@Nigule

what is the win rate increase when player strength increases by one stone in the OGS rating system.

To answer that question, besides the rating calculations, you also need a conversion formula to convert between ratings and go ranks. That conversion formula basically determines the rating gaps between go ranks. It’s mostly independent of the rating system, as long as rating gaps in the rating system are compatible with the Elo scale.

That conversion formula is applied on top of the rating system. OGS has their own empirically determined conversion formula, and it is similar to the EGF empirically determined conversion formula (at least in the kyu range).

Also see:

2021 Rating and rank adjustments

I made a quick plot of Elo per rank for the new rating to rank formula: [image] Red curve is from the new OGS conversion formula Blue curve is from the new EGF conversion formula (to be implemented soon) Horizontal axis is the OGS rank (0 = 30k, 30 = 1d, 42 = 13d = new max rank in EGD) Vertical axis is the Elo width per rank. In the range of 30k - 5k, it is quite a close match (30-70 Elo per rank). So the new OGS formula will make OGS kyu ranks as soft/tough as EGF kyu ranks and I expect …

From those conversion formulas (ignoring the g function and RD parameters of Glicko):

• a 15k is expected to win 56% of their even games against a 16k on OGS and EGF
• a 1d is expected to win 62% of their even games against a 1k on OGS and 64% on EGF
• a 7d is expected to win 66% of their even games against a 6d on OGS and 76% on EGF