No, you have predictive capacity to tell that this player will likely win against 3d players. The ranks on Tygem are discrete, so there is by definition a range of skill within a particular skill bracket.

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be immersed

To confirm that would require comparing win rate data in even games between Tygem 3d's and 4d's...

My goodness, Mef. I think you're just being silly now. I've given you data from a number of players, and we can see people that have played thousands of games, winning around half of them against evenly matched players.

What more do you want?

If the guy I linked shouldn't be 4d, then what should be be? 3d? Why? He wins half the time against 4d. 5d? Why? He loses half the time against 5d. He's at 4d, and that's just right - he wins half the time and loses half the time.

I'm satisfied with having provided data for people to make their own decision. I encourage everyone to try it out and make their own opinion.

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be immersed

I've told you quite simply what I want: I want Tygem's rating system to make a set of predictions on rated games, and I would like to see it evaluated on how accurate those predictions are. This has been my stance from the very beginning (even in the other thread!) and has not changed. Showing that players have 50% win rates over 8000 games where you do not know who those games were played against means very little. You should expect Tygem's players to have a range of win rates between 33% and 66%, because these are the promotion/demotion bounds. If Tygem's rating system is overwhelmed by random noise, then it makes sense that all players have 50% win rates.

Yes, you'd like the system to be KGS's. I understand.



This is your speculation. Take any player that has had several thousand games, and show me how it is overwhelmed with random noise. I've already shown you such a player, and we could see that his games were against people of his same rank. This is not noise. Like I said earlier, I know that you will not change your opinion. You are a KGS admin, and you like KGS's system better.

And to be honest, in some regards, I enjoy KGS's ranking system as well.

But calling Tygem's ranking system a farce is BS, and I have a good amount of experience playing on the server to know that it's not true. Based on your comments, I'm fairly confident that I have more experience than you. I've also shown you games to show you that we have consistent wins and losses. Since there are so many players there, unlike KGS, so most games are not handicap games. That's why, when someone has a stable rank, we can expect 50% win rates.

In any case, this conversation is not going anywhere, and I believe I've provided evidence that Tygem's system is a viable one, even if some KGS admins think of it as a farce.

I won't comment again in this thread.

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be immersed

Oh well, probably because nobody wants to listen. I prefer to go down a rank or two after a losing streak of - say - 5-10 games (at least in the kyu ranges) and try a new start-up at the lower rank (as long as I know it would not take too long to climb up again). It will probably help me to get over my slump quicklier... So I second Oren to make the system a bit more dynamical. Otherwise (and apart from the 2d?-bug) I like the KGS system most (comparing to Tygem, WBaduk, IGS-Pandanet).

As for creating new accounts, I think many do that, because you can easily do it and KGS doesn't deprecate it. There may be other reasons to create a new account. Those players who play tons of games (>20 per day) are clearly the minority. However the original question "Does KGS rank system encourage users to make new accounts" applies in other cases as well. I am one of the players who rarely play - in 99% I just watch tournament events, such as the Dutch championship last weekend. When I am in the mood to play, my idea is a plan to play more often. Then I create an account and play a few games until the rank has stabilized. The point is, that I always use "automatch" to play games (because it's the only way for me to jump over the wall and get a game). Unfortunately the plan will never be realized, and the one day of play remains the only day of play. After a while, the rank of that account drifts to "2d?" (even if you haven't played for more than 180 days), and when I am in the mood again, I don't want to use that "2d?" account, since I feel that I don't deserve to play anyone of that strength without handi stones (it would probably be different, if I were really around 2d). Then I create a new account again (and use the old one for watching). So in a way the buggy KGS ranking system is responsible for users who regularly create new accounts.

Like the "got stuck" problem this is only *one* reason to create new accounts. There may be others as well that I don't know of.


Good sunmmary for Tygem. I'd just add that the predictive power is significantly better in the 1-6d range. In the kyu ranges it is abysmal (18k are usually stronger than 5k).


This probably applies to 5-18k players as well, however you will very often play with (same ranked) players who are actually 10 stones stronger or 10 stones weaker (and these are *no* exceptions). So the pure number of wins/losses has probably little significance.

The big issue for KGS, and why Tygem is better predictive, is the lack of games for higher ranked players. Huge parts of the day go by with no games going on stronger than 4d-5d. These small samples hurt the whole system, its just basic statistics.

The answer to the OP's question is clearly "yes."

If it wasn't, then more people would have just one account. But many have two or more, including some of our fellow L19ers. What is their motive? Who cares, the system encourages people to do it, so they do.

I found the Kirby v mef argument interesting, but irrelevant to the discussion at hand. The question wasn't which is best, the question was does KGS encourage multiple accounts.

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- Brady
Want to see videos of low-dan mistakes and what to learn from them? Brady's Blunders

It covered interesting ground, but the summary I got from it is 'Mef prefers kgs's accuracy and Kirby prefers tygem's volatility', without any real change of opinion.

I would answer 'yes' as well. However, I think that this is a smaller influence than some other factors. Probably the ability inherent in KGS to make new accounts is the primary reason why people make them.

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North Lecale

I think the uncertainty (from the player's point of view) about their current rank and what would be required to reach the next rank might be part of it. The KGS rank graph generates a lot of myths mainly because people don't understand it. Whilst I don't think Tygem's system will tend towards accurately ranking people it's simple for anyone to understand even a child. Which might be a lot of the attraction to it (and to systems like Elo which are equally easy to understand).

I think that a more useful question would be: Does KGS rank system encourage well informed users to make new accounts?

In other words, are we contemplating a defect in the system or a defect in the users?

( Full disclosure: Yes, I have more than one account.
I am almost certainly a poorly informed user. )

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Help make L19 more organized. Make an index: https://lifein19x19.com/viewtopic.php?f=14&t=5207

I don't think that's a more useful question than the one asked. If the system appears to give more volatility to new users (which it does), then people will create new accounts.

There are also more reasons for multiple accounts than concern about rank. I know people with "anti-social" accounts for when they just want to play and not chat to anyone (the lack of a Do Not Disturb tag for KGS being a core reason for this), people with "drunk" accounts for when they can't stop themselves from playing after a few drinks (how well this works seems to vary ) and so on. Both of these are accounts made about rank concerns but not really because of KGS's ranking system.

This has more to do with Tygem than KGS, but to inject a little data into the conversation about volatility of ratings, I ran a short simulation with the following assumptions:

win 50% against equally ranked opponent
win (55,60,65,70)% against opponent with rank-1
win (60,70,80,90)% against opponent with rank-2
promote/demote after winning 70%/30% of previous 20 games
reset win rate counter after promotion or demotion

In general, players spend significant time at the "wrong" rank. The detailed results depend strongly on the assumed win/loss rate for unequal ranks, which is the feedback mechanism for rank convergence:

55% win rate against rank-1 ==> 44% of games played at correct rank
60% win rate against rank-1 ==> 58% of games played at correct rank
65% win rate against rank-1 ==> 66% of games played at correct rank
70% win rate against rank-1 ==> 70% of games played at correct rank

Changing the recent history promotion/demotion counter from 20 games to 30 games has the following effect:

55% win rate against rank-1 ==> 53% of games played at correct rank
60% win rate against rank-1 ==> 70% of games played at correct rank
65% win rate against rank-1 ==> 78% of games played at correct rank
70% win rate against rank-1 ==> 83% of games played at correct rank

Interesting! This may be enough of a tangent to merit its own thread in the tygem forum. A couple questions:


1: Does this include the double promotion rule for if you win 90% of your games?

2: How much would we expect this to change if we allowed a feedback loop (e.g. if 25% of the time you are incorrectly rated, this also means that 25% of the time your opponent is incorrectly rated as well...these could play into each other)

Edit: it looks like you may have already answered #2 above

I think separating blitz and non-blitz accounts is also relatively common.

I don't think the system encourages this behaivour, but people think it does.

Now i'm a fan of the KGS-system but let me explain my point with two "extreme" players.

Player A and Player B both have a stable real life rank, say at least SDK. Player A plays a lot on KGS, he has a huge game history and his KGS-rank has converged to his real life rank.

Player B rarely plays on KGS, so his game history is pretty empty and his rank is ?.
If Player B would start playing on KGS more, his rank will rapidly converge to his true rank.

Now consider both players improve their rank "offline", through study. Player Bs rank will converge rapidly to his new rank, the one of Player A not, because he has a huge game history. This is what people percieve as the systems problem. But i think the problem lies in how Player A percieves the system. If A is playing an average of 10 games/day a single game is not so important. What is a single loss if you play 9 other games that day? If A is not improving that is how he sees the games i presume. It's only for fun and the single game doesn't have that much weight on him.
But if he thinks he has improved this changes. Now he sees each win as a proof of his improvement and is annoyed by the fact that KGS doesn't weight these games as much as he does. So he creates a new account, where each new game has a much heigher weight on the rank.

The problem doesn't lie in the system but in the users. Also improvement is a gradual process it is not discrete (even if the ranks are). Especially in the SDK and Dan-ranks it takes a long time actually improve one stone. If A would keep his 10 games/day during his months of study his winning rate would rise over time. (From 50% to 55% to 60% and so on) And then when he finally self-promotes himself in real life, or has earned enough rating to start with a higher rank at a tournament, KGS has already learned that A has improved a bit. Not enough yet to also promote him, but it may take fewer games than if A had stopped playing on KGS during his improvement (what all these thought experiments of "offline" improvement seems to assume).

Player B on the other hand (an experience i had several times) has no such problem but enjoys the benefit that the system can give him an fairly accurate rank after just a few games.


I think here is where you make a mistake. First of all, the ?-mark after the rank shows everyone that this rank is not guranteed to be accurate, so your opponent knows you may not be a real 2d. You could also just open new games and state your assumed "real" rank so people know what to expect and play with the right handicap.
And if you - like me - prefer automatch, just play. Because the ?-mark also means KGS will rapidly change your rank after each game. So you will only have to play 1-3 games at fairly wrong ranks.

Since i had times were hardly played at all, i was often in the position of having each game having a heavy influence on my rank. And a normal loosing streak could easily change my stable 2k-rank to 3k or even 4k. But i knew, it would just take me one win against a 5k (which was to be expected from the next game, as my real strength was still 2k) to correct it. Sometimes i feel sorry for the 5k which would get me as their next opponent, but i always hoped i may provide him with a good learning experience.

Inaccurate ranks can always happen in any system, as no system is perfect. But KGS is good at correcting these mistakes rather quickly, which i find the best possible effect.

I also have an account on IGS but haven't played there for years. I'm a 7k there and i don't play there because it would literally take me dozens of games to correct this rank. And every lost game (which still happen from time to time) would push me further back. I really prefer the KGS-system over IGS.

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Magics way up the hill (personal study journal)

1: Does this include the double promotion rule for if you win 90% of your games?
No, I did not include the double promotion rule. I suspect this would have almost no effect, assuming you are already reasonably close to your correct rank.

2: How much would we expect this to change if we allowed a feedback loop (e.g. if 25% of the time you are incorrectly rated, this also means that 25% of the time your opponent is incorrectly rated as well...these could play into each other)
This should introduce more noise and hence make ratings more volatile, but I tried it and saw no difference.

Well, the situation I was thinking more about is that if you were over/underrated then got corrected, you are already very close to the double promotion/demotion line...you would expect overcorrections maybe 10-15% of the time? (because if you have already won enough games to promote, now it's just a matter of winning 3 of the next 4...or maybe 4 of the next 5). I think you would expect this more at the kyu levels (which use only a 15 game history and lower winning percentage cut offs).