Does Glicko Rating System Work Well With CC?

I'm wondering why the Glicko Rating System was selected for this site, a correspondence chess site?  I'm also wondering how many others are finding it impossible to play enough games in order to get a low RD and therefore are forever doomed to high fluctuations in rating?

i don't like the rating system used here. If I lose to a person rated the same as me, I lose 20 points, where as if I win to somebody rated the same as me, I get 10 points added. Within the last week, I have lost more than 150 rating points!!

What is the Glicko rating system, and what does RD stand for?  Pardon the ignorance.

 The Glicko rating system is a method of determining chess ratings.  It uses a factor called RD (rating deviation) to attempt to determine your playing strength based on how active you are.  The more games you play in a given time period, the lower your RD is and therefore, the less your ratings will fluctuate.  My question is whether this system is right for correspondence chess? 

What Glicko himself had to say:

"The system does not conserve rating points - and with good reason! Suppose two players both have ratings of 1700, except one has not played in awhile and the other playing constantly. In the former case, the player's rating is not a reliable measure while in the latter case the rating is a fairly reliable measure. Let's say the player with the uncertain rating defeats the player with the precisely measured rating. Then I would claim that the player with the imprecisely measured rating should have his rating increase a fair amount (because we have learned something informative from defeating a player with a precisely measured ability) and the player with the precise rating should have his rating decrease by a very small amount (because losing to a player with an imprecise rating contains little information). That's the intuitive gist of my extension to the Elo system."

Basically, the more you play, the smaller the fluctuation in your rating.

That would make sense if one game was an accurate sample of your playing strength.  The fact is we haven't leaned anything (or only very little) informative in the situation described because the sample size is so small it's statistically insignificant.  Lets make coin flip analogy, Flipper A has a long history of flipping, and it is known that he wins a coin flip around %50 of the time.  Well here comes Flipper B.  He's new to the flipping scene and we don't know much about him.  if he wins a flip against Flipper A is it reasonable to expect him to win %100 of future flips?  Of course not!  He only fliped one flip!  We don't have enuogh information to make that judgement.  If he continues to win all flips THEN we would have something to base such a claim on.  This is probably the stupidist thing I've ever writen.

Not many comments.  Nobody has any thoughts?

True.  My question, though, is whether the Glicko Rating System is appropriate for correspondence chess given each game takes much longer to complete and unless you play many games all at once, you will always have a high RD and therefore never an accurate rating!

That's because you don't understand the system.  I doubt anyone on the entire site has both the same rating and RD as you, and someone with the same rating but different RD is, for the sake of determining rating adjustments, NOT Rated the same.

So, in order for someone to have a moderate RD such as 50 in your case, they must play between 30 and 50 games simultaneously.  For a high rated/experienced chess player, this is probably a manageable number of games.  But, for beginners like myself, who have to labor to find a good move in many situations, playing that many games simultaneously results in very poor moves and many losses.  Losses that would not have likely occurred if fewer simulataneous games were being played.

So, for someone who can only play ten or fewer games simultaneously, under this rating system they are forever doomed to an RD around 100 and wil never achieve an "accurate" rating!  However, the admins of this site could reduce the requirement of games played per time period in order to achieve an RD of 30.  I hope the admins have not just blindly applied the Glicko Rating System to their website without fully understanding its ramifications.

You are right that it's hard for the glicko system to give you an accurate rating if you don't play a large amount of games.

However, the traditional ELO method would be even less accurate.

Isn't an RD of 100 inaccurate by definition?  We are saying that if someone's "true" rating of 1550 was somehow absolutely known that we are satisfied by calling it anywhere between 1450 and 1650?  That doesn't seem so accurate!  However, if the RD was 30, for example, I could live with calling that person's rating between 1520 and 1580.

RoundTower wrote:

 I don't think this is true.  Gaining/losing 30-50 points per game because of an RD over 100 seems to be a very poor way to calculate a CC player's rating if they play fewer than 30-50 simultaneous games.  The ELO method would be more accurate in this instance.

You can't just say "Well, since people don't play as many games as otherwise, all of these ratings are going to be considered more accurate than they are."

The short answer= "NO". Nor is it satisfactory for LIVE CHESS imo. My rating here is the worst anywhere by hundreds of points. And it feels a little ridiculous to go up and down from 1400 to 1700 here and back down again in a day or two of time. I'll win 20 or 30 or games vs players at my rating and get maybe 5 points per game. Then lose two games to equally rated players and have up to 45 points taken from me for EACH of those losses. It is simply ridiculous. Had I not played till tired and lost my last two (or my first and last game of the day), would I REALLY be 90 points STRONGER as a player?! No way.

And it does not jibe with ELO on other sites. And is not a particularly good feeling to know you are a Master in Corr with 6 other orgs; and being 1950 to 2100 in LIVE & Blitz everywhere else, but fighting a battle up to 1700 here, or 1600 after a bad day, only to lose it back as soon as risking that loss that comes when tired or the board starts freezing or stealing your last 6 seconds off the clock.

No one game should ever be That significant in any valid rating system. Elo is much better. And there are ways to utilize Provisional Ratings, Bonus Points, and "K"-factor changes that can make it as quick to give a True Established Rating as any valid system and can adjust out any over inflation or deflation as well, using the tools available in ELO.

I do like the fact here that there are three separate ratings for LIVE, based on different Time Controls used. That is a positive. But about the Only Positive of that entire rating quagmire. imho ( & even moreso, in my 'unhumble' opinion )

}8-)

PS.. in the end it comes down to this: What sensible rating system can take two losses vs 20 wins against players all of same rating area as you, and judge that the two results are Equal ... leaving you at the same rating as you started with before that days effort? It is nonsensical mathmatically and statistically.

it's not really about how many simultaneous games you play but how often you complete your games.  For example some players finish most of their games in a month, others more like 5 months.

If you only complete, say, 1 game a week, then you will have a fairly inaccurate rating, and a fairly high RD, so your rating will fluctuate by, say, 30-40 points a game.  If we used the ELO system with a low k-factor (say 24) your rating would be equally inaccurate, but it wouldn't fluctuate as much (12 points a game on average).  So you could get an established rating of 1700 and really not be much better than most 1500s, but the rating system would take a long time to get that right.  This would be nice for you if you were overrated, but you could equally well get an established rating of 1500 and really be strong enough to compete with 1800s, especially if you are an improving player.

maybe the best way to put it is that the ELO system would give you an illusion of having a stable rating, even though on average it will be less accurate than the glicko one.

 Oh my.  What I have been trying to get at summed up in one sentence!  Thank you BaronDerKilt.  I agree wholeheartedly!

Thanks for the explanations!  I learned something new

One's true rating is not possible to know, but this site's use of the Glicko System for CC players is, in my opinion, horribly flawed.  The solution is to reduce the number of games one must play per time period in order to achieve a low RD.  Why is a low RD important?  Because with high RD's come wild fluctations in rating (which happen on this site WAY more than on any other chess site I've played on) and therefore it is impossible to even estimate one's chess playing strength. 

With all of that said, I am not claiming to be the world's foremost expert on the Glicko, hence the title of this thread.