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.

People do so love their illusions. 

But, the Glicko System is assuming you have started and finished and played in only one game in that week and therefore that your chess skils are getting rusty.  But, while playing CC chess, you have more games going simultaneously and the result is that you are using your chess skills continuously even though, perhaps, only one game concluded in that week.  Do you think both of these scenarios are equal?  The Glicko System as is applied on chess.com is saying that they are!

Yes, I do think it is a good system for CC.

Like you, I don't play too many games simultaneously and have a fairly high RD. My rating is very inflated currently and I have started playing people of a similar rating, so I fully expect it to take a serious dip in the next few months. That would be fair. If I win half and lose half of the games against the similarly rated players then my rating will oscillate for a while (possibly quite dramatically), but will end up around the same as I am now, which would also be fair.

I play a lot of lower rated players in tournaments. If I lose to one of these guys my rating will dip by 60 points. Fair enough. If I lose to these guys then my rating ought to take a serious beating.

In summary, my rating is not reliable because I don't play enough games, so it will possibly change quite dramatically. This is appropriate. If someone plays a lot then their rating is more reliable, so it shouldn't change by much. If one chooses to play few games so as to concentrate more on individual games then their rating might be better than someone who plays a lot of games simultaneously, but is still statistically less reliable, so I think it is the fairest possible system.

Fair engouh.  I can respect your opinion.  But, I don't think one should have to play 30-50 simultaneous games in order to prevent wild fluctations in rating.  I mean, I play chess every single day.  No, I don't complete games every single day.  But, I am quite sure that my chess skills are not getting worse just because I do not complete a game every single day.  The Glicko system as is applied here on chess.com is penalizing me for not completing games every single day!  It is asserting that I am, in fact, getting worse at chess even though I'm playing the game every day!

 Key Point: Your rating is not your actual rating.  What do I mean by that?  Well, Glicko (and other ratings) are mathematical representations of what your true rating is.  No one really knows what their true rating is, since 1. it changes over time, and 2. it requires a large number of games to accurately determine.  The best we can do is approximate your actual rating by using a formula.  The main reason that Glicko is used is because it actually suffers less from errors than other systems.

Now, on Chess.com, does 1500, 1700, etc. mean you are a bad player?  NO, nothing could be farther from the truth!  Ratings are a product of the population they exist in, and they mean very little outside that population.  To say that, "correspondance Chess shouldn't use Glicko", is a very meaningless viewpoint, since the number doesn't translate at all towards what that person's USCF or FIDE number is.  The best you'll be able to say is that of two players, rated 1500 and 1700 on this site, the 1700 is most likely to have a better game.  Anything other than that is ignorance.

The system here works correctly, and if it doesn't "jibe well with ELO on other sites" (by the way, Elo is a name, not an acronym), then the problem is either that the competition is better/worse on the other site, or their system is flawed (typical if it is based on rewards rather than performance).

 You didn't touch on the main idea of this thread.  You just talked about how a rating is never a true rating and that the ratings here are valid only within our population.  Both are true statements.  But, should the Glicko System for CC as applied to chess.com take into account the fact that not everyone can play 30-50 simultaneous games which provide enough finished games per day to get an RD closer to 30 than the much more common 100+ ?

My advice to the creator of this topic is play people in incriments.  Play people 100 pts. plus or minus from your rating.  When you consistently beat this group, your rating will improve.  My current rating is close to 1700, with my average opponent a shade over 1400.  Also, moderate your opponents ability.  Play six games around your same rating and play a few 200 pts below and above.  This will help alleviate the fluctuations of the ratings system.  Always plan on a few you can win, and others you expect to challenge, mixed with some in your range.  It has really helped me improve. 25% below, 50% in proxi to your rating, 25% above.   Hope this helps. (It may not make sense, but I tried)

 Thanks for that info.  I am not, though, concerned with my rating, since I am overrated!  I just want chess.com to use the very best rating system available and I believe a modified Glicko would be more appropriate for CC.  Others disagree with me and they may very well be right, but so far I think it could be improved!

I think you are misunderstanding how it works.  It doesn't think you are getting "rusty" or "worse at chess" from not playing.  Quite the opposite, in fact: it makes it easier for you to gain rating points if you have improved at chess.

 Basically, what I think he's saying is... take a break. =)

RoundTower wrote:

 It does indeed.  Each day that goes by without a finished game increases your RD.  This by definition means that the Glicko system thinks your rating has become more uncertain. 

you are contradicting yourself.  No, it does not think you are getting "rusty" or "worse at chess".  It thinks that it is now less certain of what your rating should be.  Which makes sense.

It doesn't judge that you've got worse (or better).  It merely acknowledges that there is a decent chance you could have got better (or worse!) since last it checked.

I think you should read carefully my posts and the webpages where the details of glicko are explained.  It may well be possible that it could be improved, but it's not very productive for you to suggest ways to change it when you don't really understand how it works.

Good point.  I understand it just fine, just mistyped.  It certainly can, and I believe should be improved, though.

First, I would say that glicko is the correct system. I've done a fair bit of looking around at rating systems, and I understand the statistics involved, and glicko is the best I've seen so far. Now, that defines "best" in terms of most accurate reported rating. That may not be what you're looking for in a rating. It sounds like you want a more precise rating. Not the same thing.

Second, the problem may not be in the system, but in the constants. Some have suggested a switch to elo, but elo is actually glicko, just with different values for the constants than are normally used for glicko. I have not seen anywhere on this site exactly which values are used for the constants here.

Third, I'm not seeing the problem. I'm not playing very many games, and my past few ratings adjustments have been a handful of points each. I'm looking at a potentially significant shift in the near future, but I'm about to beat someone rated 300 points higher than me. Maybe it's a perspective issue more than a system issue.

Being somewhat of a math dude, even though I am not familiar with the algorithm

of the Glicko and not even altogether familiar with the Elo, it can be said that an

algorithm is fair and accurate if it does not discriminate between players and the players are familiar with the rules of the rating game itself. Ratings are only methods of matching players, that is all that they are for. A rating does not mean anything except as a comparison with a particular player with an average over a group of players and of games.The truth abut players is about the matches actually played and who won and lost. But math does not know to whom a particular number or game result belongs to. That is the beauty of math, as Bertrand Russell said.  Math is only a comparison of data so that a potzer does not unwillingly or unknowingly play a grand master and vice versa.