Life In 19x19
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KGS Ranking adjustment?
http://www.lifein19x19.com/viewtopic.php?f=24&t=15681
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Author:  RobertJasiek [ Tue May 05, 2020 10:42 am ]
Post subject:  Re: KGS Ranking adjustment?

You can "justify" any rating system (such as "the rating is a constant 1900") by saying "calculates the true rating according to the rating system". Bullshit! A good rating system can be recognised by producing numbers that are meaningful from external analysis and easily understood by human perception. I have never seen either for the KGS rating system. It is nothing but a black box that works in itself and justifies itself internally claiming to reveal eternal truth for the external observer, until an admin admits nonsense by readjusting some parameters.

Author:  lodestone [ Tue May 05, 2020 3:19 pm ]
Post subject:  Re: KGS Ranking adjustment?

I don't think the peculiarity you noticed is due to the frequency at which the rank updates, I think it is due to the fact that it looks at all recent history for your previous opponents as it updates.

For instance, if I win a game against someone who is currently listed at 5kyu, but who is rapidly improving so that one week later they are up to 2kyu, the KGS rating system will treat my win as though it was against a 2kyu player instead of a 5kyu player.

That means that as my vanquished opponent's rank is improving, mine is also drifting upward along with it. That is most of the reason that rank on that server tends to drift around even when you haven't played games recently.

Author:  Harleqin [ Tue May 05, 2020 6:15 pm ]
Post subject:  Re: KGS Ranking adjustment?

Bullshit yourself. You just can't separate the noise from the signal mentally, and seem unable to grasp what the signal itself is saying.

KGS' ranking algorithm certainly is far from perfect, but at least it is a more plausible effort to actually estimate strength than all ELO-based systems, especially given the paucity of data. If you want to gamble for points, then it may seem off to you, but gambling for points is, in the end, incompatible with actual strength estimation.

If you don't like the mechanisms of the KGS rank meta-game, then don't play it. Ignore the rank graphs and just be content that it gives you reasonably strong opponents.

Author:  RobertJasiek [ Tue May 05, 2020 9:23 pm ]
Post subject:  Re: KGS Ranking adjustment?

Harleqin wrote:
KGS' ranking algorithm certainly is far from perfect, but at least it is a more plausible effort to actually estimate strength than all ELO-based systems


I find the EGF rating system (ELO) to be (far from perfect but) very much more meaningful than the KGS rating system.

Quote:
just be content that it gives you reasonably strong opponents.


Nice theory, but in practice on average it does not. Among same-ranked opponents, I get players that play between ca. 1k and 6d real world ranks.

A simple rating system, such as +0.1 ranks for a win, +0 for a jigo, -0.1 ranks for a loss, would be much better.

Author:  jlt [ Tue May 05, 2020 11:50 pm ]
Post subject:  Re: KGS Ranking adjustment?

RobertJasiek wrote:
Among same-ranked opponents, I get players that play between ca. 1k and 6d real world ranks.


People don't always play at the same level on the internet. The 1k wanted to play a relaxing game after a hard day's work and his baby started crying during a complex fight. The 6d was more concentrated because he wanted to recover the rank he lost the day before due to a disconnection problem.

RobertJasiek wrote:
A simple rating system, such as +0.1 ranks for a win, +0 for a jigo, -0.1 ranks for a loss, would be much better.


That's more or less the IGS ranking system. Indeed it works reasonably well and is easy to understand, the only drawback is that you need to play 20 games before you get a firm rank (without "?" at the end).

Author:  Harleqin [ Wed May 06, 2020 2:24 pm ]
Post subject:  Re: KGS Ranking adjustment?

That's what I meant with gambling for points.

Such a system only works reasonably well, if

- the participants are paired randomly (otherwise subpopulations emerge that have different points distributions)
- each participant continually plays a lot of games (otherwise the noise of temporarily inactive players suddenly appearing with a different actual strength leads to different frustrations)
- the mechanisms for getting new points into the system in order to represent actual strength growth match the actual strength developments (otherwise there will be rating drifts and waves, but this is totally unmeasurable anyway)

It is very implausible that these assumptions are even remotely approximated.

So, all you get is gambling for points. That's simple and good for the endorphine rush of a simple mind, but that's all it is.

Author:  Uberdude [ Wed May 06, 2020 5:59 pm ]
Post subject:  Re: KGS Ranking adjustment?

From some testing a while ago (few games in history, previous opponent turning rank on and off) I concluded the KGS rank recalculation is done of the order of every 10 seconds.

Author:  RobertJasiek [ Thu May 07, 2020 9:25 am ]
Post subject:  Re: KGS Ranking adjustment?

Uberdude, why then are rating graphs updated only once a day?

Author:  jlt [ Thu May 07, 2020 10:10 am ]
Post subject:  Re: KGS Ranking adjustment?

Updating graphs every 10 seconds would use too much computing resources.

Author:  RobertJasiek [ Thu May 07, 2020 10:22 am ]
Post subject:  Re: KGS Ranking adjustment?

Updating graphs (copying an already calculated rating) must require much less computing power than updating ratings (calculating rating).

Author:  jlt [ Thu May 07, 2020 10:34 am ]
Post subject:  Re: KGS Ranking adjustment?

Don't know.

15kB (size of a rank graph) * 20 languages * 30000 users = 9 gigabytes

do you want to update that every 10 seconds?

Author:  RobertJasiek [ Thu May 07, 2020 10:22 pm ]
Post subject:  Re: KGS Ranking adjustment?

Are you suggesting that rank graphs would be distributed as pictures instead of rating numbers?! Does CGoban not generate the rank graph picture from only receiving rating numbers only when the user opens it?!

Author:  jlt [ Thu May 07, 2020 11:19 pm ]
Post subject:  Re: KGS Ranking adjustment?

Actually I wrongly thought that rank graphs were stored as images. The rank graph in english of a given user can be visualized on

Code:
http://gokgs.com/servlet/graph/nicknameoftheuser-en_US.png


I didn't notice the URL contains "servlet", which suggests that the image is generated at each request.

Author:  Uberdude [ Fri May 08, 2020 2:29 am ]
Post subject:  Re: KGS Ranking adjustment?

RobertJasiek wrote:
Uberdude, why then are rating graphs updated only once a day?


You'd have to ask wms, but I presume a combination of pragmatism, necessity, and laziness.

Author:  jlt [ Thu Dec 31, 2020 7:35 am ]
Post subject:  Re: KGS Ranking adjustment?

Does anybody else feel that KGS ranks have become weaker?

I looked at the table from a 2018 survey https://idex.github.io/go-rank-survey/g ... mean-ranks and circled my current ranks.

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Author:  gennan [ Thu Dec 31, 2020 9:09 am ]
Post subject:  Re: KGS Ranking adjustment?

Possibly, and OGS ranks seem to have grown tougher recently.

A very recent survey lines up OGS 4k = KGS 1k (= EGF 3k = IGS 2k = Fox 1k = Tygem 1d). Though some of the results in that table look a bit suspicious to me, like the AGA dan levels.

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Author:  jlt [ Thu Dec 31, 2020 9:39 am ]
Post subject:  Re: KGS Ranking adjustment?

So the recent table shows that in the 1-5k range, KGS ranks have become about 1 stone weaker.

(And I agree that AGA 5d = EGF 6-7d is highly suspicious.)

Author:  jlt [ Thu Jan 28, 2021 12:26 am ]
Post subject:  Re: KGS Ranking adjustment?

The "OGS" column is now obsolete, since ranks have been adjusted. Mine has moved from 5k to 2k.

Author:  Knotwilg [ Thu Jan 28, 2021 2:08 am ]
Post subject:  Re: KGS Ranking adjustment?

FWIW this anecdotal evidence. About 10 years ago I was very active on KGS and had a stable 2d ranking. In the 10 years that I have been just casually playing, I dropped down to 1d, which seems fair. Nowadays I'm playing and studying intensively again and my rank has gone up to 2d. It all feels natural and fair and not an inflationary effect. If I look at other players who have been there for more than a decade I can see most are around the same level too. We may become weaker as we age but I hope and think not to the extent of a full stone.

As reported elsewhere, I'm 1k on OGS and 4d on Fox. That again seems to make KGS fairly well calibrated. But I'm just one data point of course.

Author:  jlt [ Thu Jan 28, 2021 5:59 am ]
Post subject:  Re: KGS Ranking adjustment?

Apparently the ranking adjustment on OGS moved your rank to 2d, which is in line with your other ranks on go servers or in real life.

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