That is exactly what I had in mind.

My reason to "force" random pairing is that I want a lot more handicap games. Right now, the overwhelming majority of rated games are even. How can we hope to get the correlation to handicap stones right this way?

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A good system naturally covers all corner cases without further effort.

Huh? Sorry, if the overwhelming majority of rated games are even, why does the correlation to handicap stones even matter?

However, where are your stats to support: 1. the "overwhelming majority" and 2. the lack of correlation to handicap stones? It has been more than 10 years since I played on IGS and I have not played a significant number of games on tygem but my impression is that the percentage of handicap games on KGS has always been relatively high.

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Dave Sigaty
"Short-lived are both the praiser and the praised, and rememberer and the remembered..."
- Marcus Aurelius; Meditations, VIII 21

I believe he was meaning to speak in the ideal case. If a primary goal of the ranking system is to properly match up handicap games (and properly space ranks via handicap stones), it makes sense that you would want a large number of handicap games in your dataset (probably >50%, I'm not a well-versed statistician who could give you an exact number though). As far as ratio of even to handicap games....just glancing down the active games list, in the first 35 rated games I count 8 handicap. I then scrolled about halfway down the list to the 4-6k section, and found similar numbers (7-8 handicap games in about 35 rated games....the list changed a little while I was counting). So it looks like a reasonable guess would be 20-25% of rated games on KGS are handicapped (I didn't look at the time systems to see if even or handicap was more likely to be blitz, that could skew things). I don't know about how many handicap games are played on other servers, but I would make a guess that as the number of players on a server go up the percentage of handicap games go down (since from my anecdotal experience a majority of the population prefers even to handicap, and more players = more opportunity for an even game).

Good news for the rating nerds, you mean! And I'm not much of a rating nerd. I just want something that does a good job of matching players up and a reasonable job of tracking progress, then I pretty much lose interest in the topic of ratings.

Sometimes though, a person's progress can be strongly linked to the form of rating being used. If a person's rating progresses too slowly compared to their actual level, they won't be challenged as much and may fall back on bad habits.

A lot of getting stronger is in being challenged at the right times.

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Tactics yes, Tact no...

Well, to my knowledge, no one has ever implemented a bayesian-style updating distribution as rating. Most folks seem to be content tracking 1 number.

A player's distribution should tell you a lot, if they're strong against lower ranked players, it would be skewed one way, strong against stronger players, it would be skewed another.

But seeing as it's never been done, maybe there's a reason...

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Tactics yes, Tact no...

Rakuen has little games, but check out dex morgan.It has 80 games in the last 2 months.

I believe that i could defend a 7d on good days, which i rarely get, and im 6d on average. I always felt danigabi was under-rated, and i think dexmorgan is slightly over-rated.
Buth both accounts have almost 1.5 stone difference.

I believe this is a major psychological effect on my opponents rather than myself. And this effect i can only see on KGS, specially on high handicap.

Flashback did something similar, and so did other strong players, that giving extra handi is a rating/probability of winning success.

However the opposite is true. playing only proper handi games feels like a total drag, as losses are very hard-felt. This is from a user stand-point and the evidence is anecdotical. But i have no reason to believe opposite either.

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Founder of Kaya.gs

The reason is almost certainly that it's too much work and trouble for a very small benefit.

Of course, if we were really good proper Bayesians, we'd never assume something as preposterous (and obviously false) as the idea that strength can be reduced to a single metric (which is still the core assumption even when you're tracking a changing distribution). Instead, we'd track individual players' results against one another and then try to extrapolate stuff from that, in some much more complicated fashion. There wouldn't be numeric rankings at all, instead the system would be able to tell you your chance of winning against a specific player.

I believe that some of the problems raised could be solved using a "volatility" factor.
Please check this rating system as a possible example:
http://apps.topcoder.com/wiki/display/t ... ing+System

It would obviously need to be adapted as we have 1on1 games, but games should get more important (or "heavier") the farther from the expected outcome one gets. The 5th win in a 5win streak should increase one's rating more than a win after a win-lose-win-lose scenario.

But if we're good decision theorists and/or programmers, we'll think about the cost of various implementations both in terms of human and computer effort. A pure bayesian approach probably fails on both counts, while Shapenaji's solution might work. And if we're pragmatists, we'll say that since people will continue to fuss about rating systems until the end of time, we might as well turn that sunk cost of time into new rating system prototypes since that's still better than arguing about ratings on forums (economists will disagree).

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Occupy Babel!

So you gave a story, got challenged to provide specific games, and then responded by ...not providing specific games?

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Occupy Babel!

really?!

so if I flip a coin 10 times and it comes up heads all ten times, should I expect the probability of a heads result on the next toss to be greater than 50/50?

This reminds me of a conversation in which I tried to convince someone that, if a roulette ball lands on red 5 times in a row, the chance of it landing on red the 6th time is still slightly less than 50/50 (because of the green slot).

But, this may be slightly different than a coin toss or roulette wheel, because a streak may indicate recent significant improvement (or maybe not?).

Yes! 10 heads in a row is starting to be good evidence that you aren't dealing with a fair coin.

There is a difference between flipping a coin and playing a game of go. In go, the possibility exists that greater skill is causing the winning streak, and the longer the streak, the more probable that this explanation is plausible, no? If a flipped coin turned up heads ten times in a row, I'd also suspect that skill is involved.

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Patience, grasshopper.

That's why I (like HermanHiddema) suggested that after a number of wins, the player is matched up like a higher rank. Because of the ranking difference, he will automatically gain more rating points if he wins.

Insisting on proper handicaps in every game seems misguided to me, when the goal is to rapidly track a player's current strength. Someone might have a long winning streak against even opponents by chance, but if he keeps winning against stronger opponents, that data is much more conclusive.

Who let the frequentist in here? *shoos xed_over away*

BAYESIANS ONLY

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Tactics yes, Tact no...

I'm trying to stay out of this discussion since it is about ideas for a differenc rank system from KGS, but I can't resist adding a comment on "the 5th win in a 5win streak..." business. xed_over is right, it's nonsense for the the 5th win to mean more than the 1st win after a loss. I think the idea of each win in a streak mattering more is because, "win-win-win-win-win" should definitely increase your rank more than "win-lose-win-lose-win," so it feels like the 5th win should count for more. But of course almost any rank system will give you a bigger boost from the 5 wins than from the 3 wins and the 2 losses, so the situation is already handled without needing to give the 5th win more significance.

If the ten flips were HTHTHTHTHT, would you consider that evidence that it was a trick coin?

That is some small amount of evidence that the coin alternates heads and tails. If you can't tell, I'm very much a bayesian.