How does the rating system work?

[swarminglocusts]

What is an average player and what is an intermediate and master player ranked? How high and low does this system work?

[Kaworu_Nagisa]

Go ranks and ratings

[flovo]

OGS uses glicko2 as rating system. https://en.m.wikipedia.org/wiki/Glicko_rating_system#Determination

Here an approximation of how the rating system works:

1. Each player has a rating (500-3500) and a deviation (indicated by ±)
2. After one of your games ends, we take the last 15 games to calculate, how your rating has to change to better predict the outcome of those games.
3. The difference of you rating and your opponents rating gives an estimation for how probable it is for each player to win the game.
4. For each game the win probability, the outcome (win/lose/draw) and your deviation determine how your rating changes.

Here the ranks of the OGS player base (copied from @S_Alexander’s thread)

[BHydden]

@flovo

2. After one of your games ends, we take the last 15 games to calculate, how your rating has to change to better predict the outcome of those games.

This isn’t quite accurate. We process in batches of 15 games (or 30 days, whichever comes first), but these aren’t rolling. Your 14th game of a batch will be based on the last 14 games, the 15th game will complete the batch, then the 16th game will be the 1st of a new batch, and only compare itself with the previous completed batch.

@flovo

Here the ranks of the OGS player base (copied from @S_Alexander’s thread)

It’s worth noting that since this graph was generated

1. 17 months ago, and
2. before we implemented humble rating,

it is most likely out of date.
(and would be LOVELY if @S_Alexander were kind enough to remake it)