When is the new grading list coming out?

General discussions about ratings.
E Michael White
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Re: When is the new grading list coming out?

Post by E Michael White » Tue Aug 18, 2009 9:52 pm

I wasnt trying to suggest that 90 existed universally in each graders world. I recall one grader telling me he used 90 and another 100.

Matthew has suggested going back to a fixed starting point of about 80; I gave the the K-H example to show that a first grade of 180 wasnt a drawback in their cases. I didnt think the 40 point rule existed back then so I didnt think they were limited. Hartston may have been held back by agreeing a draw with Penrose in the London League when he was winning but I may be thinking of another year. Another grader told me back in the 60 s that he gave local grades if a player played nine games I think it was, of which at least 7 had to be against graded oppos - give that man a medal !

Roger de Coverly
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Re: When is the new grading list coming out?

Post by Roger de Coverly » Tue Aug 18, 2009 10:34 pm

I've been trying to figure out the London League guy. To recap this was a player who scored 95% against 9 graded and 1 ungraded opponent. The gradings ("new" grades) ranged from 133 to 171 and generated a performance of 219. We're all familiar with the "give to the rich" effect of the 40 point rule, so that a graded player with any start grade above 173 would get an end grade which was a function of the start grade and the higher the start grade, the higher the end grade. EMW's Markov chains indicate that the estimate should have come out as (sum (9 rated players) + ??? for the unrated +450) /10 with ??? the only variable.

On the face of it, the 40 point rule has been applied a multitude of times.

E Michael White
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Re: When is the new grading list coming out?

Post by E Michael White » Wed Aug 19, 2009 12:06 am

Roger de Coverly wrote:I've been trying to figure out the London League guy. To recap this was a player who scored 95% against 9 graded and 1 ungraded opponent. The gradings ("new" grades) ranged from 133 to 171 and generated a performance of 219. We're all familiar with the "give to the rich" effect of the 40 point rule, so that a graded player with any start grade above 173 would get an end grade which was a function of the start grade and the higher the start grade, the higher the end grade. EMW's Markov chains indicate that the estimate should have come out as (sum (9 rated players) + ??? for the unrated +450) /10 with ??? the only variable.

On the face of it, the 40 point rule has been applied a multitude of times.
Ok lets try reverse engineering this example in this strange world of markov chains, quasi statistics, indeterminate scales and information deficit where we find ourselves. I think I'm supposed to look up something on Neumann expansions to reverse this one easily but I'm not that sure how to spell it, so I had better resort to basic arithmetic and an excel spread sheet to avoid losing myself.

if he got a grade of 219 against that range of opposition he probably benefitted by about 7 or 8 from the 40 point rule; so lets go for 7, always a favourite of mine.

So we need a factory gate grade before government taxes of about 212 to balance the books.

Lets guess his graded opppos as:-
131 159 164 167 169 171 172 172 173

The 131 was probably a last minute reserve.
Lets further assume 8.5/9 against graded giving 1878 points at an average of 208.6

Now lets guess the ungraded oppo is emerging through the final iterations with a raw unbadged grade of 195 and our hero won giving him a result of 245.

His total is now 2123 looking good at 212.3 ready for final conditioning in the 40 point rule shop. His graded oppos are now treated as at least 172.3 so they are now:-

172 172 172 172 172 172 172 172 173

for a total score including 400 for 8 wins of 1949

Which together with the unrated result at 245, needing no correction, gives a total of 1949 + 245 =2194 for a final grade of 219.

Its a bit late so I may have made a slip or six.
Last edited by E Michael White on Wed Aug 19, 2009 8:52 pm, edited 2 times in total.

Matt Harrison
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Re: When is the new grading list coming out?

Post by Matt Harrison » Wed Aug 19, 2009 8:23 am

Makes sense - if you assume his opponents were that strong.

But examination of the London League results and looking up their new old grades on the database shows they were actually:

146
152
164
171
155
u/g - but with 2007 grade of 134
151
133
146

Scoring 8.5/9

Now he played another game somewhere (which I can't find), but to get 1878 grading points from his 9 graded opponents, his missing game must have been a win against someone graded 260 as his 8 games against graded opponents generate 1568 points (grade of 196 from these 8 games).

Looks to me like the recursion routine has had the 40 point rule applied to each iteration.

And I'd be surprised (pleasantly so) if the actual routine used was as sophisticated as the routines postulated in this thread (which had my brain ticking over - 25 years since I finished my maths degree, and I've barely thought about maths in the meantime).

Matt Harrison
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Re: When is the new grading list coming out?

Post by Matt Harrison » Wed Aug 19, 2009 8:31 am

My guess is that pass 1 just uses the games between 2 graded opponents to set their grades. Then pass 2 works out the grades for ungraded players based on their games against graded opponents. Then pass 3 works out the grades for ungraded versus ungraded. Then pass 4 redoes the entire grading using the values obtained from passes 1, 2 and 3. This is re-run until the grades converge. And I suspect the 40 point rule is included in each pass.

Kevin Thurlow
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Re: When is the new grading list coming out?

Post by Kevin Thurlow » Wed Aug 19, 2009 8:41 am

I seem to recall a BCF grader saying a few years ago the list was out and was "90 % accurate", which I took to mean that he thought 90 % of the arithmetic was correct, even before you allowed for the wrong results being inserted occasionally (and it is easy to enter a wrong result, whoever you are), and before you allowed for estimated grades being well off the mark. Apparently 90 % was considered ok.

I am arbiter at Thanet Congress this weekend, which is always enjoyable (and hard work).

This year is particularly exciting.
(a) The first tournament for most of us under new FIDE Laws.
(b) The first tournament using the new ECF pairing rules (although as there's a computer, I might use the old ones...)
(c) The first tournament using the new gradings. I predict a weekend of
(ci) "I entered the Minor - why am I in the Major (or Open!)?"
(cii) "Explain the new gradings to me."

In fairness to the organisers, who always do a fantastic job, the entry form does say that anyone transferred to a higher section due to new grades does have the option to withdraw and receive a full refund if they tick the box on the entry form.

I plan to have a large noticeboard saying "we are using the new grading list" and "Please refer all questions about the grading list to ECF".

This probably won't work as chessplayers don't read notices.

I will report back on this....

So far there have been a lot of theoretical arguments on this thread, but this offers the chance to see how it works(?) in practice!
"Kevin was the arbiter and was very patient. " Nick Grey

E Michael White
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Re: When is the new grading list coming out?

Post by E Michael White » Wed Aug 19, 2009 8:43 am

Matt
Rogers data showed 9 graded and 1 ungraded
Yours shows a 2nd ungraded which would make a difference.

Roger de Coverly
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Re: When is the new grading list coming out?

Post by Roger de Coverly » Wed Aug 19, 2009 9:01 am

E Michael White wrote:Matt
Rogers data showed 9 graded and 1 ungraded
Yours shows a 2nd ungraded which would make a difference.
I think it's actually 9 graded and 1 ungraded. Richard James who is presumably familiar with London League competitions and website structure was able to find the tenth result - but the rest of us haven't.

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Carl Hibbard
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Re: When is the new grading list coming out?

Post by Carl Hibbard » Wed Aug 19, 2009 9:07 am

Sean Hewitt wrote:
John Upham wrote:My sources inform me that there was a very recent ECF Board meeting at which this matter was discussed and it was decided to ignore the disaster that is the new rating list on the grounds that it would sort itself out within a year!
Neill Cooper wrote: I hear that the grading team met last weekend to consider various of the issues which had been raised with them (e.g. through the 'contact' page on the grading website, and some emails). They are making further calculations which I hope we will hear about in due course (by next weekend). So something is being done to improve matters. That is about all I know.
So, which is it?!!
The second one is closer to the mark
Cheers
Carl Hibbard

Matthew Turner
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Re: When is the new grading list coming out?

Post by Matthew Turner » Wed Aug 19, 2009 9:15 am

I have to admit to finding this difficult to follow, but I think there are two important points that you may be missing.

1. Were any of his opponents juniors, because if there were then their new old grades are irrelevant?
2. Which game did he draw? surely if he drew with the ungraded player this would make a difference (in simple terms the ungraded player would come out higher than normally expected because he had drawn with a 219!)

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John Upham
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Re: When is the new grading list coming out?

Post by John Upham » Wed Aug 19, 2009 9:19 am

Carl Hibbard wrote: The second one is closer to the mark
Carl,
Does this mean that you are being kept informed? if so, by who? This must have come as a shock!
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Roger de Coverly
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Re: When is the new grading list coming out?

Post by Roger de Coverly » Wed Aug 19, 2009 9:33 am

Matthew Turner wrote:
1. Were any of his opponents juniors, because if there were then their new old grades are irrelevant?
I don't think they were - but it's a very good point that the "throw away juniors prior grade" rule now makes it much more difficult to audit a grading calculation.

The idea seems to have been floating around for a while. It had a "no plans to" status last year when Jack Rudd got wind of it.

http://www.ecforum.org.uk/viewtopic.php ... 2835#p2835


Matthew Turner wrote: 2. Which game did he draw?
It was against a player graded 135 in the 2008 published and 151 as 2008 red.

Mike Gunn
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Re: When is the new grading list coming out?

Post by Mike Gunn » Wed Aug 19, 2009 9:40 am

As I'm at least partly responsible for the "two versions" of what the ECF is doing/ has done, perhaps I should make clear what I know.

As president of the SCCU I invited comments from other SCCU officers and affiliated organisations about the new grades (and specifically the junior grades). On hearing that the ECF board had decided to take no action I wrote to Chris Majer and he told me that the board had merely "noted" that new grades had been calculated (there was no discussion or decision). Chris asked the director responsible (Cyril Johnson) to look into the concerns and he (CJ) subsequently contacted Neill Cooper and myself to let us know that the grading team would be looking at the issues. I have no idea who is involved in this (apart from the grading manager Dave Thomas). I understand that some changes could be made to grades at the end of August revision, but there is a limit to what can be done because of the time factor.

E Michael White
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Re: When is the new grading list coming out?

Post by E Michael White » Wed Aug 19, 2009 9:58 am

Matt Harrison wrote:u/g - but with 2007 grade of 134
If this player had no 2008 grade 2007 would not necessarily be used instead.

I do not know whether the ECF changed the rules this year but previously any 2008 rapidplay result would have been used instead and he would have been treated as graded for the purpose of calculating the grades of others. I raised this in the past with the grading team as not entirely satisfactory.

Is this the G C Taylor Grade ? I wasnt paying much attention when this discussion started up.
Last edited by E Michael White on Wed Aug 19, 2009 10:21 am, edited 2 times in total.

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Carl Hibbard
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Re: When is the new grading list coming out?

Post by Carl Hibbard » Wed Aug 19, 2009 10:01 am

John Upham wrote:
Carl Hibbard wrote: The second one is closer to the mark
Carl,
Does this mean that you are being kept informed? if so, by who? This must have come as a shock!
The answer to that would be NO however it's pretty clear that something is wrong and further investigations are in progress...
Cheers
Carl Hibbard