Rough Guide to new grades

General discussions about grading.
TomChivers
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Re: Rough Guide to new grades

Post by TomChivers » Fri Mar 27, 2009 5:04 pm

John Hickman wrote:I can see next year playing in FIDE rated tournaments against juniors and losing FIDE rating but gaining ECF rating :?
So, if I understand the grading systems correctly, this would happen in games that are drawn, but where you are rated higher than the junior on the FIDE lists, and lower on the ECF lists. In other words, where a game is drawn and the ordering of the FIDE list is different to that of the ECF list. And presumably, such a thing might happen already in some cases, and not just with juniors.

This in fact suggests quite a good test of the ECF list, viz., is the ordering of the new ECF grades closer to the ordering of the FIDE grades, than the old ECF grades were? (Assuming, that is, FIDE grades are typically more accurate than ECF ones.)

Roger de Coverly
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Re: Rough Guide to new grades

Post by Roger de Coverly » Fri Mar 27, 2009 5:27 pm

(Assuming, that is, FIDE grades are typically more accurate than ECF ones.)
Surely for most of us below IM standard, the converse is true. I doubt if more than 30% of my games are FIDE rated. FIDE ratings are based on results in selected events against a subset of opponents.

One of my 4NCL team mates contrived to get an initial FIDE rating in the 1800s despite many years of having an ECF grade in the 170/180s. I'm told that his next FIDE will finally start with a 2. He's been trying to offset the inflation in the 1900-2100 FIDE range by scoring all the points for the team.

Matt Harrison
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Re: Rough Guide to new grades

Post by Matt Harrison » Tue May 26, 2009 11:02 am

I was talking though the new grades with my son and his friend (both aged 15). They were aware of the regrading and will be 'benefiting' from a moderately substantial increase to their grade. However they are both very much against the regrading. They consider that they've worked hard on their chess, and their grades are reaching a decent enough level that they no longer have to put up moans and groans from adult opponents. But come next season everyone will just assume they are now over-graded and get annoyed when they are pushed up onto higher boards for league matches. My son's grade will go from 138 to 170ish (it would have been 162 on old grades). They feel that if they reach a decent standard on old grades then this will be more respected than on new grades - but no-one will know this, they'll just assume they've been booted up by 35 points.

They made the point that if the reason to change the grades is to enable people to trust them more as they will be more accurate in predicting results, any benefit from this will be offset by the lack of trust in the new grades - simply because they're new, and because people who have always been 150 are now 160-170.

Of course, any correlation between their opinions and the fact that their new grades will force them to play in Open sections next season and say goodbye to hopes of supplementing their income with prize money is completely accidental :D
(although to be fair, my son did point out that under old grades he'd be up from 138 to 162 next season in any event and would still have to play in the Open section of many tournaments.)

Roger de Coverly
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Re: Rough Guide to new grades

Post by Roger de Coverly » Tue May 26, 2009 12:30 pm

They made the point that if the reason to change the grades is to enable people to trust them more as they will be more accurate in predicting results
If a grading system was 100% reliable as a predictor, no grade would ever change.

Any grading system is going to be a hybrid between current and historic performance which means that recursive recalculations are never going to reproduce begin period published grades. Brian Valentine did some notes on the effect of random fluctuations in performance. One of his points was that if you ran an all play all of 10 players with the same grade, one of the least likely results is that every player scores 50% - but that is the "predicted" result from the grading system. John Nunn in the context of the international system coined the phrase "rating lag" to discuss the issue most noticeable with improving players that the grade takes a "while" to catch up with current performance. There is a trade off that changing the grade rapidly to reflect recent results can cause excess fluctuations in the grades of players whose standards have not changed.

There's another way of looking at the changes and that is to look at the grading distance between the "average" player and the GM you might encounter in a weekend open. If you define "average" as the grading range in the middle so there are as many graded players above as below, then the distance between the "average" and the GM is being reduced from about 120-125 points down to 95-100 points. The new grading scale could be anything they wanted it to be, so they could have left the "average" player where they were and reduced the GMs down to about 205. Everyone would have thought this completely ridiculous but it's equivalent to what's happening.

My prediction for the future is that the 120 point gap will reassert itself but the "average" may stay around the 130 mark. This will propel the 230 GMs up towards 250.

Paul McKeown
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Re: Rough Guide to new grades

Post by Paul McKeown » Fri Jul 03, 2009 3:54 pm

Sean Hewitt wrote:I'm not overly concerned about the finite numbers (whether a player is 100, 150 or 1276!) as long as he scores 75% against a player who is graded 25 points below him.
Sean, it has been pointed out many times on this forum that this 75% "predicted score" is being abused. For example by myself and exhaustively and convincingly by Brian Valentine.

I will quote myself for the sake of convenience:
Paul McKeown, Re: New grades (split from Editorial thread), Wed Sep 03, 2008 2:55 pm wrote:A chess rating is an ESTIMATE of a statistical parameter not the actual value. So it can never be known for certain that a player is 1700 Elo player. Sometimes he plays as a 1600 player sometimes as an 1800 player. Assume that a given player is 100% certain a 1900 player (an impossibility of course) who plays a player with a 1700 rating. Elo tables predict a 76% result for the stronger player. But what if the weaker player plays 50% of the time as a 1600 player and 50% of the time as an 1800 player? Then the stronger player will achieve 50% of his anticipated score against a 1600 and 50% of his anticipated score against an 1800, which is 0.5 x (0.64 + 0.85) = 74.5%. In otherwise, because of the uncertainty in the playing strength of the weaker player, the stronger player will not achieve his "theoretical" Elo score.
At the time I wrote that there were some burblings from the shires about, "but we use the Clarke system", which I found very dull, as the principle is the same.

I could of course have quoted some more recent and much more theoretically grounded analysis by Brian Valentine to the same effect. Or alternatively I could have quoted A Comprehensive Guide to Chess Ratings, by Professor Mark E. Glickman, one of the reference works on this subject.

All with the same conclusion, the "75%" is not a prediction, but an upper limit to the predicted score of the higher ranked player.

What is being done to the grading system is vandalism, pur sang, supported by dubious analysis, opposed by most of the chess public who have had grades for long periods and see no obvious reason to assume that grades are not reasonably correct, and rammed down their throats by an acolytic clique of believers.

The grading system will not be improved one jot by this exercise and no doubt a change to an Elo based system will follow within a few years as a corrective consequence of this damaging upheaval.

Paul McKeown
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Re: Rough Guide to new grades

Post by Paul McKeown » Fri Jul 03, 2009 3:59 pm

I would like to congratulate Roger de Coverly for his persistent campaign to demonstrate the folly of this change. I wish I had his endurance!

Sean Hewitt

Re: Rough Guide to new grades

Post by Sean Hewitt » Fri Jul 03, 2009 4:32 pm

Paul McKeown wrote:...opposed by most of the chess public who have had grades for long periods and see no obvious reason to assume that grades are not reasonably correct...
Wow! You've canvassed the majority of the chess public have you? I certainly haven't.

But of those that I have spoken to the majority believe that there has been deflation in the grading system for years (long before I started playing again). They can't quantify it, nor know how to correct it, but they know that the problem is there.

John Upham
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Re: Rough Guide to new grades

Post by John Upham » Fri Jul 03, 2009 4:33 pm

Paul McKeown wrote:I would like to congratulate Roger de Coverly for his persistent campaign to demonstrate the folly of this change. I wish I had his endurance!
A persistence in common with King Canute : http://en.wikipedia.org/wiki/Cnut_the_G ... _the_waves
British Chess News : britishchessnews.com
Twitter: @BritishChess
Facebook: facebook.com/groups/britishchess :D

Paul McKeown
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Re: Rough Guide to new grades

Post by Paul McKeown » Fri Jul 03, 2009 5:08 pm

Sean Hewitt wrote:Wow! You've canvassed the majority of the chess public have you? I certainly haven't.

But of those that I have spoken to the majority believe that there has been deflation in the grading system for years (long before I started playing again). They can't quantify it, nor know how to correct it, but they know that the problem is there.
Actually, most people I have heard just snigger about it in terms of their free grading points.
Last edited by Paul McKeown on Fri Jul 03, 2009 5:55 pm, edited 1 time in total.

Paul McKeown
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Re: Rough Guide to new grades

Post by Paul McKeown » Fri Jul 03, 2009 5:18 pm

Sean Hewitt wrote:... there has been deflation in the grading system for years (long before I started playing again). They can't quantify it, nor know how to correct it, but they know that the problem is there.
Well, that may or may not be true, but the present vandalism in no way attempts to establish the causes of the putative deflation in order to remove them. It is instead a futile one off exercise in inflating the grading system. Within 2 or 3 seasons the established order will have re-established itself by a mechanism of passing the grading bonuses back up the grading list.
Sean Hewitt wrote:of those that I have spoken to the majority believe
Possibly true. My observation is that if you ask players with low grades why they have low grades they are happy to grab onto the idea that it is the fault of the grading system, rather than the possibility that they are just crap at chess.

Paul McKeown
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Re: Rough Guide to new grades

Post by Paul McKeown » Fri Jul 03, 2009 7:23 pm

E Michael White wrote:... one thing is for certain if the grades are started at 100 the resulting grades would be between 50 and 150 as long as there is no 40 point rule. John Upham would get his absolute zero concept of 50 and Michael Adams would be pushing 150.
Based on "White's Certain Scale", Mickey Adams should really be only 25 points better than a player currently graded 185 or so. I don't know any 180's or 190's who would fancy their prospects of scoring 25% or better against Mickey Adams. Bizarre. How on Earth do you manage to come up with that proposition?????

I don't know where you live, but I'm sure that the final line of the address must read, "An Alternative Reality".

Sean Hewitt

Re: Rough Guide to new grades

Post by Sean Hewitt » Fri Jul 03, 2009 8:11 pm

Paul McKeown wrote:
Sean Hewitt wrote:of those that I have spoken to the majority believe
Possibly true. My observation is that if you ask players with low grades why they have low grades they are happy to grab onto the idea that it is the fault of the grading system, rather than the possibility that they are just crap at chess.
Who mentioned anything about asking players with low grades?

Paul McKeown
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Re: Rough Guide to new grades

Post by Paul McKeown » Fri Jul 03, 2009 8:16 pm

Sean Hewitt wrote:Who mentioned anything about asking players with low grades?
My experience is that the only players who thing this makes any sense whatsoever are low graded, seemingly delighted that they were never really 114, but really 134, or 69, but really 100. The majority just regard it with cynical amusement.

Sean Hewitt

Re: Rough Guide to new grades

Post by Sean Hewitt » Fri Jul 03, 2009 8:18 pm

Paul McKeown wrote:
Sean Hewitt wrote:... there has been deflation in the grading system for years (long before I started playing again). They can't quantify it, nor know how to correct it, but they know that the problem is there.
Well, that may or may not be true, but the present vandalism in no way attempts to establish the causes of the putative deflation in order to remove them.
You're half right there. The cause is actually well known, but there appears to have been either no attempt to correct the problem on an ongoing basis, or those involved aren't able to to implement a viable solution.
Paul McKeown wrote:It is instead a futile one off exercise in inflating the grading system. Within 2 or 3 seasons the established order will have re-established itself by a mechanism of passing the grading bonuses back up the grading list.
To be fair to the ECF, that's definitely wrong. They were concerned that a corrective exercise would be inflationary and one of the reasons that they delayed doing anything was to ensure that your scenario wouldn't occur. Whether they will be successful we will have to see.

The answer to that will hang on what they end up doing with junior grades.

Sean Hewitt

Re: Rough Guide to new grades

Post by Sean Hewitt » Fri Jul 03, 2009 8:19 pm

Paul McKeown wrote: My experience is that the only players who thing this makes any sense whatsoever are low graded, seemingly delighted that they were never really 114, but really 134, or 69, but really 100. The majority just regard it with cynical amusement.
That's certainly not my experience.

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