Rating system

[nagano]

How does this work exactly? I know it's based on the number of wins and losses but if you win or lose more than one game in a row, it seems to do strange things.

[karaklis]

Which system are you actually talking about? There are different systems.. KGS? EGF? AGA? IGS? WBaduk?

[Solomon]

Which system are you actually talking about? There are different systems.. KGS? EGF? AGA? IGS? WBaduk?

Probably the server that this subforum is for .

How does this work exactly? I know it's based on the number of wins and losses but if you win or lose more than one game in a row, it seems to do strange things.

What exactly do you mean by "strange things"? The system simply looks at a window of your last 20 games and, depending on how well you do, promotes/demotes from there. I haven't played there in a while, but if you win 14 out of your last 20 games or something like that, you'll get bumped up a rank; win 18 out of 20 and you get bumped up two ranks. Same for when you lose 14/18 out of your last 20, then you get demoted.

[karaklis]

Probably the server that this subforum is for .

Touché

It's just difficult to see in which subforum you're in when accessing the forums via "view unread posts" or "view new posts"..

[nagano]

What I mean is, if you win two or more games in a row, the loss counter sometimes resets, and if you lose more than one game in a row the win counter will increase the number of games you need to win disproportionately to the number you lost. Mostly I have noticed these things when I have played less than 20 games at a given rank.

[snorri]

Reviving this thread since I don't think the question was answered. Is the Tygem rating system documented somewhere?

[yoyoma]

People are all saying it's:
Win 14 of last 20 = promotion
Lose 14 of last 20 = demotion

An example of one of the strange things the "last 20 games" can do:

Start with 13 wins, 6 loses:
13W 6L

You need 1 win to promote, 8 losses to demote.
Lose:
13W 7L

Now you have a full 20 game history, and failed to get 14 wins. But now your early wins will start dropping off. So suddenly you go from needing just 1 more win, to needing 13 wins(!) to promote. Because each game (win or lose) will drop one of your first 13 wins.

(12W) 1W 7L 13W = 14W in last 20 = promote.

The overall effect is strings of wins/losses have a big impact.


ETA: I don't know how the double promotion part works into this.

[Kaya.gs]

People are all saying it's:
Win 14 of last 20 = promotion
Lose 14 of last 20 = demotion

An example of one of the strange things the "last 20 games" can do:

Start with 13 wins, 6 loses:
13W 6L

You need 1 win to promote, 8 losses to demote.
Lose:
13W 7L

Now you have a full 20 game history, and failed to get 14 wins. But now your early wins will start dropping off. So suddenly you go from needing just 1 more win, to needing 13 wins(!) to promote. Because each game (win or lose) will drop one of your first 13 wins.

(12W) 1W 7L 13W = 14W in last 20 = promote.

The overall effect is strings of wins/losses have a big impact.


ETA: I don't know how the double promotion part works into this.

This system is terrible. How sure are we that it works this way? I would be very surprised that such a big server has such an unsophisticated rating system.

[karaklis]

This system is terrible. How sure are we that it works this way?

We are sure that it does not work. It occurs frequently that an 18k can defeat a 4k without handi stones. In the dan ranks it seems to be better though.

[hyperpape]

Karaklis: that's a (slightly) separate problem related to people setting their initial ranks. Of course, if the system were like that of KGS, those ranks would rapidly correct themselves (funny that Tygem ends up being less flexible in one regard).

[mw42]

Positive. The rating system looks at 20 game groups (for dan, 15 for kyu). Once you reach a point where no further promotion/demotion is possible it resets, promotes/demotes accordingly, and begins a new group.

[snorri]

Positive. The rating system looks at 20 game groups (for dan, 15 for kyu). Once you reach a point where no further promotion/demotion is possible it resets, promotes/demotes accordingly, and begins a new group.

So if I understand correctly, if you are 7/7, it should reset because there would be only 6 games left in the 20 and no way to get 14 wins or losses, right?

[oren]

Positive. The rating system looks at 20 game groups (for dan, 15 for kyu). Once you reach a point where no further promotion/demotion is possible it resets, promotes/demotes accordingly, and begins a new group.

So if I understand correctly, if you are 7/7, it should reset because there would be only 6 games left in the 20 and no way to get 14 wins or losses, right?

There is no reset. It always looks at the window of your previous 20.

[lovelove]

I think the Tygem rating system is a simple and good rating system. I personally like most, or maybe just more used at.
This system is used widely in all Korean go servers except one, wBaduk. There are eight or more go servers in Korea.

They always check your winning rate from the last 20 games (for dan, 15 games for kyu).
If this winning rate is higher than 70%, rank will promote.
If lower than 30%, rank will demote.
Else, rank will remain, but still continue checking the records of last 20 games. At any moment hitting 70 or 30 percent winning rate, rank will change.

When rank changes, you need at least to play 20 games for another rank change.

There are some special promotion, when the last 20 games winning rate is higher than 90%, you can promote twice at once.

Only problem in this system is that people can remain rank with only 30~40% winning rate, and sandbaggers can keep their rank by not just going over 70%.

This is based on traditional jubango system, where the player with more than 7 wins will play as white without komi next time, which means he is one stone stronger than his opponent.

[topazg]

I have ended up with a preference for simple system over a mathematically intricate system for playing on. There are huge amounts of factors (such as creating new accounts, deliberately sandbagging etc) that make for a far bigger impact than the intricate maths of theoretically "superior" systems. IGS and Tygem both have very simple systems yet I find myself preferring them every time I play on the different servers.