Problems Accessing the ECF Grading Database?

General discussions about grading.
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Reg Clucas
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Re: Problems Accessing the ECF Grading Database?

Post by Reg Clucas » Mon Jan 26, 2015 10:24 pm

Jon Mahony wrote:I played at Stockport RP yesterday, and did quite well, beating two 138's and drawing with a 139 so it's going to go back up in the summer! :cry:
The 139 you drew with was actually a 138, but has now gone down to 135, so that will save you 1/10th of a grading point! :wink:

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David Shepherd
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Re: Problems Accessing the ECF Grading Database?

Post by David Shepherd » Mon Jan 26, 2015 10:41 pm

Carl Hibbard wrote:Fair play to Pigott, John C with a 269 at number 3 but it's really rather silly.
Still if you quick through on the link to the FIDE rating, his rating is 2384 so fair to assume he is reasonably strong and the other option of him being ungraded could also be a bit misleading.

Brian Valentine
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Re: Problems Accessing the ECF Grading Database?

Post by Brian Valentine » Mon Jan 26, 2015 11:31 pm

Roger de Coverly wrote:
Brian Valentine wrote: Pigott has only 6 games counting for grading and he won them all.
At the time of the grading revaluation, it was speculated that the algorithm for estimating the grade of a new player could converge to an unexpectedly high value where the percent score was in the 85% to 100% range and presumably to a low value if the score was 0 to 15%. We cannot see who he played with the system currently being down, but if you had a player with a grade of 259 playing five games against 209 players, that would be a performance and thus a new grade of 269.

There are a couple of players from Poole also with F grades in the top 100.
I got it wrong one game was before the cut off so here are the games:

Ref Opponent Club Grade Result Board Date
144163C Spearman, David Wanstead 189 A 1 1 24/11/2014
106666D Berry, Stephen H Wimbledon 220 A 1 W 1 30/10/2014
179196F Lexton, Mike J St Albans 180 C 1 1 15/12/2014
259449D Tiruchirapalli, Venkataramanan Watford 221 A 1 1 29/10/2012
285691J Suarez Real, Alberto Wimbledon 220 D 1 W 1 04/10/2012

You will see that he had no games in 2012-3 period so he is treated as a new player.

During the iteration phase he gets a starting grade of the average grade of his opponents +50 giving to 256. The calculation then goes through the games again giving him at least 256+10. The new average becomes his final grade of 269.

I'm not going to do this for any other cases, but I am happy to provide facts to the debate. Please note Neil Cooper's mail showing the other side of the coin for F player issue.

I'll see what I can provide for E Michael White, but I do not have the figures in a suitable form to hand. I set out some figures in an earlier post explaining why the "traditional measure" was distorted by the number of relatively weaker new F grades now admitted and there will be similar issue arising from his statistic muddying the waters (although the effect on his statistic will be diluted because F players play relatively fewer games).
Brian
Last edited by Brian Valentine on Tue Jan 27, 2015 7:40 am, edited 1 time in total.

Roger de Coverly
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Re: Problems Accessing the ECF Grading Database?

Post by Roger de Coverly » Mon Jan 26, 2015 11:42 pm

Brian Valentine wrote: Ref Opponent Club Grade Result Board Date
144163C Spearman, David Wanstead 189 A 1 1 24/11/2014
106666D Berry, Stephen H Wimbledon 220 A 1 W 1 30/10/2014
179196F Lexton, Mike J St Albans 180 C 1 1 15/12/2014
259449D Tiruchirapalli, Venkataramanan Watford 221 A 1 1 29/10/2012
285691J Suarez Real, Alberto Wimbledon 220 D 1 W 1 04/10/2012

You will se that he had no games in 2012-3 period so he is treated as a new player.
If you did it the really old fashioned way of grader's estimate, you would probably suggest something in the range 220 to 230. It not as if he hasn't been playing for over forty years. So at 220, this avoids any 40 point issues and brings him in at a performance of 256.

I assume that the rule on F grades is that they don't actually count towards their opponent's performance before being recalculated.

For young or inexperienced players, it can make sense to ignore the history. Is it really right to do this for players with an established history over 200?

Angus French
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Re: Problems Accessing the ECF Grading Database?

Post by Angus French » Tue Jan 27, 2015 1:13 am

David Shepherd wrote:
Carl Hibbard wrote:Fair play to Pigott, John C with a 269 at number 3 but it's really rather silly.
Still if you quick through on the link to the FIDE rating, his rating is 2384 so fair to assume he is reasonably strong and the other option of him being ungraded could also be a bit misleading.
Though if he was ungraded he would also be an ex-233-grade player.

Brian Valentine
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Re: Problems Accessing the ECF Grading Database?

Post by Brian Valentine » Tue Jan 27, 2015 7:39 am

Roger de Coverly wrote:
I assume that the rule on F grades is that they don't actually count towards their opponent's performance before being recalculated.
His opponents get the grade 256 as the starting grade for the calculation.

Brian Valentine
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Re: Problems Accessing the ECF Grading Database?

Post by Brian Valentine » Tue Jan 27, 2015 8:17 am

E Michael White wrote: As said somewhere else on this forum you should really be concentrating on grades weighted by number of games played as an index, which is generally more meaningful particularly in these circumstances.
If one disregards games played by those who have no grade then this index would be 139.2 for the August 2014 list. This number drops to 137.7 in the January 2015 list. If one then disregards game played by F grades (who would have had no grade under the old rules) the index rises to 138.8

Jonathan Bryant
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Re: Problems Accessing the ECF Grading Database?

Post by Jonathan Bryant » Tue Jan 27, 2015 9:17 am

David Shepherd wrote:
Carl Hibbard wrote:Fair play to Pigott, John C with a 269 at number 3 but it's really rather silly.
Still if you quick through on the link to the FIDE rating, his rating is 2384 so fair to assume he is reasonably strong and the other option of him being ungraded could also be a bit misleading.

True, not giving Mr P a grade might also be misleading. It wouldn’t make the grading list look "silly", though. Publishing a list with him at 3rd highest does. Carl has chosen absolutely the right word.

If you want a credible grading list this kind of thing really needs not to happen. There’s not much point having one if you’re going to say, 'oh but ignore that one because ..., ignore this one ... and that one ....". There’s a reason why cricket batting average tables usually come with a stipulation 'minimum of 10 completed innings' or some such.

Which is not to say I think F grades are a bad thing per se. You just need to have a think about how you’re going to present them.

Roger de Coverly
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Re: Problems Accessing the ECF Grading Database?

Post by Roger de Coverly » Tue Jan 27, 2015 9:21 am

Brian Valentine wrote: His opponents get the grade 256 as the starting grade for the calculation.
I was thinking more about what a potential opponent in 2015 will be credited with. Is it like playing a junior that you don't know and cannot know until July 2015?

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Christopher Kreuzer
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Re: Problems Accessing the ECF Grading Database?

Post by Christopher Kreuzer » Tue Jan 27, 2015 10:01 am

Jonathan Bryant wrote:Biggest drop ever. Lowest grade since the ratings readjustment.

Officially fit for the chessic knackers yard.
:lol: Only one point below me. I would say that bouncing back is easily done but I think the changes introduced more lag. Still, I doubt your grade dropped as much as mine did last January. I lost 26 points in Jan and gained 22 in July. Last time there were changes like that to my grade was an increase of 27 to my second published grade of 128 in 1994. Normal changes are around 10 grading points or less.

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David Shepherd
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Re: Problems Accessing the ECF Grading Database?

Post by David Shepherd » Tue Jan 27, 2015 10:23 am

I agree with Jonathan above - it is partly a matter of how the grades are presented. So in my head I interpret the F grades as being very unreliable but at least an indication of how the player has performed over a very small number of games. So for example it would be sensible for the f grade players not to be included in a search of the top players as the grades are too unreliable.

I guess another way of dealing with ungraded players who have previously been graded would be to include players on a grading list at their last grade but with an I code for inactive.

Roger de Coverly
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Re: Problems Accessing the ECF Grading Database?

Post by Roger de Coverly » Tue Jan 27, 2015 10:38 am

Christopher Kreuzer wrote: Still, I doubt your grade dropped as much as mine did last January. I lost 26 points in Jan and gained 22 in July.
Presumably you had a run of bad results between July 2013 and December 2013. It's still a bit odd, as your July was an X grade and December an A. Perhaps your December A just included a 30 game count back, rather than all the available games from 2013.

The rule now is that a whole year of your most recent games will always be counted. So your performance from July to December 2014 will determine in part your grade in July 2015.

Angus French
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Re: Problems Accessing the ECF Grading Database?

Post by Angus French » Tue Jan 27, 2015 10:56 am

Roger de Coverly wrote:
Brian Valentine wrote: His opponents get the grade 256 as the starting grade for the calculation.
I was thinking more about what a potential opponent in 2015 will be credited with. Is it like playing a junior that you don't know and cannot know until July 2015?
The Manager of Grading previously stated: "Category F grades will be published like any other grade, but they will not be used in future calculations."

Angus French
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Re: Problems Accessing the ECF Grading Database?

Post by Angus French » Tue Jan 27, 2015 11:04 am

Jonathan Bryant wrote:Which is not to say I think F grades are a bad thing per se. You just need to have a think about how you’re going to present them.
... and how you're going to use them: Should they be used in competitions to determine player eligibility and board orders?

Roger de Coverly
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Re: Problems Accessing the ECF Grading Database?

Post by Roger de Coverly » Tue Jan 27, 2015 11:17 am

Angus French wrote: Should they be used in competitions to determine player eligibility and board orders?
If existing rules allow players without grades to take part "on the estimate of the organiser or controller", The F grade can replace the estimate. It's trickier for deciding eligibility for grading prizes and sections.

Congresses will have to decide whether they regard F grades are legitimate. If nothing else, they are a guide to strength.

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