New grading conversions

General discussions about grading.
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Joey Stewart
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New grading conversions

Post by Joey Stewart » Fri Jan 03, 2020 4:13 am

If we must suffer a change in English grading numbers, I was wondering if there is some sort of formula already devised that will convert current ECF ratings into new 4 digit ones.

Also, do we know the formula being used for the new system, so players have an idea what sort of changes they might expect based on their recent results?
Lose one queen and it is a disaster, Lose 1000 queens and it is just a statistic.

Roger Lancaster
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Re: New grading conversions

Post by Roger Lancaster » Fri Jan 03, 2020 10:29 am

ELO = [7.5 x ECF] + 700

Ian Thompson
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Re: New grading conversions

Post by Ian Thompson » Fri Jan 03, 2020 12:30 pm

Joey Stewart wrote:
Fri Jan 03, 2020 4:13 am
If we must suffer a change in English grading numbers, I was wondering if there is some sort of formula already devised that will convert current ECF ratings into new 4 digit ones.

Also, do we know the formula being used for the new system, so players have an idea what sort of changes they might expect based on their recent results?
See:
https://www.englishchess.org.uk/monthly-grading-proposal/ wrote:
  1. At inception of the Elo system current grades will be converted using the formula: new = 7.5*old + 700 (assuming the ECF want to move to a 4-digit system aligned at that point to FIDE)
  2. There will be extended deadlines for the July list to facilitate late reporting and corrections. This will be the principal list.
  3. Each month, all previous monthly lists after the last principal list will be recalculated to take into account late reported results.
  4. All results dated in the last month, plus some brought forward (see below) are collected and current grades assigned to each player. These records are then duplicated so that there is a record of each result is considered for a player point of view with each opponent.
  5. These half-results are split into 4 groups: both graded(“gg”), only the player graded(“gu”), only the opponent graded(“ug”), both ungraded(“uu”)
  6. The grading formula is R1 = R0 +k(W-We) where R0 is the grade for the previous month, k is 20 or 40, W is the player’s total score for results in the month, We is the expected total score based on the FIDE table 8.1b – https://www.fide.com/fide/handbook.html ... ew=article
  7. The ug results are first graded and these grades are inserted into the gu and ug groups. These groups are then combined with the gg group and all these results are then graded for each player.
  8. The uu group are carried forward to the next month for potential grading then.
  9. Each ungraded player will be deemed to have drawn with an 1850 graded opponent as an extra result on initial grading.
  10. The k factor will be 20 except that in a month where a junior player has outperformed expectation, then the k factor will be 40.
  11. These grades are to be used for grading calculation only. Some sifting will be required for seeding or section limits, as outlined above.

Ian Thompson
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Re: New grading conversions

Post by Ian Thompson » Sat Jan 04, 2020 11:34 am

https://www.englishchess.org.uk/monthly-grading-proposal/ wrote:
Each ungraded player will be deemed to have drawn with an 1850 graded opponent as an extra result on initial grading.
I'll take Brian's word for it that this works well for junior players new to the grading system, but what about (very) strong foreign players who enter the ECF grading system when they play in an English tournament for the first time?

Nick Grey
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Re: New grading conversions

Post by Nick Grey » Sat Jan 04, 2020 3:18 pm

What is the basis of 1850? It is too high compared to me and is insulting to most adults and current junior chess players.
Is it the midpoint?
This ought to inflate grades in the new system.

Why not grade them as 90 plus the relevant conversion in the new system for the extra result on initial grading?

AndrewBanks
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Re: New grading conversions

Post by AndrewBanks » Sun Jan 05, 2020 7:09 pm

Nick Grey wrote:
Sat Jan 04, 2020 3:18 pm
What is the basis of 1850? It is too high compared to me and is insulting to most adults and current junior chess players.
Indeed... I almost want my existing grading expunged from the record! A draw against a 1850 (ECF 153) would be a career high ;)

dejan_lekic
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Re: New grading conversions

Post by dejan_lekic » Tue Jan 07, 2020 1:42 pm

Assuming they have historical data, with all results for past N years, I wonder why do they not calculate ELOs from scratch instead of converting existing ECF grades to ELO? This would ensure most accurate ELO ratings. - Sure this is computationally heavy process, but it can be done extremely fast if properly distributed (I kinda know little bit about these things being software engineer for 20+ years).

Roger de Coverly
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Re: New grading conversions

Post by Roger de Coverly » Tue Jan 07, 2020 2:11 pm

dejan_lekic wrote:
Tue Jan 07, 2020 1:42 pm
This would ensure most accurate ELO ratings.
Elo theory relies to an extent on player strength being reasonably consistent and stable, neither of which is true when new players and juniors are involved. It's also necessary to fudge the issue of initial ratings a bit when starting from a clean boot with absolutely no prior ratings. I seem to recall that even the International system did a warm boot of sorts during the 1970s by importing conversions from national systems regarded as reliable, such as the USCF and BCF.

dejan_lekic
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Re: New grading conversions

Post by dejan_lekic » Tue Jan 07, 2020 2:38 pm

Sure, that is why there is the "k" factor in the formulae, and it is precisely why I think grades should be calculated using historical data - because the process can calculate the k-factor as it processes the data...

Roger de Coverly
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Re: New grading conversions

Post by Roger de Coverly » Tue Jan 07, 2020 2:59 pm

dejan_lekic wrote:
Tue Jan 07, 2020 2:38 pm
Sure, that is why there is the "k" factor in the formulae, and it is precisely why I think grades should be calculated using historical data - because the process can calculate the k-factor as it processes the data...
I do not believe the K factor on its own is sufficiently powerful to revalue rapidly improving players. Many national Elo based systems have had to introduce various adjustments to deal with this. The Scottish version will treat players who have improved by "x" as new players. In other words if they have evidence that a player is playing to a 1600 standard, they would throw way the rating that says he's 1200. I think their "x" is 200.

The ECF' proposed method is an asymmetric k for juniors coupled with in effect a minimum rating for new players.

Nick Grey
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Re: New grading conversions

Post by Nick Grey » Tue Jan 07, 2020 10:44 pm

:D The half rating ought to have been set at 1150 not 1850. May equate to 60 ECF but has been ages since we assumed all new players were graded 90 which converts to 1375. 1850 is madness for a first result. Get the starting point right at 1150 please. :D

Roger de Coverly
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Re: New grading conversions

Post by Roger de Coverly » Tue Jan 07, 2020 10:57 pm

Nick Grey wrote:
Tue Jan 07, 2020 10:44 pm
1850 is madness for a first result. Get the starting point right at 1150 please. :D
I suppose the idea is to ensure a minimum rating for new players. I would be more concerned about under rating new players from outside England. But perhaps their FIDE or other Elo based rating would be imported as their initial estimate.

The problem of negative grades only began to emerge when local graders were no longer allowed to set estimates for new players. If you assume in the absence of other evidence that all new players are ECF 100 or even ECF 50, it injects points into the system and supports a floor minimum grade.

Nick Grey
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Re: New grading conversions

Post by Nick Grey » Tue Jan 07, 2020 11:56 pm

I think the biggest issue is to get ECF Membership before getting a graded game when currently they an pay late in June 2020. Bronze members are a big part. I think 60 is better than 90. 100 is too high and 50 is too low for an adult. Anyway I hope to see you again at 4NCL soon.

John Hodgson
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Re: New grading conversions

Post by John Hodgson » Tue Jan 14, 2020 4:21 pm

Ian Thompson wrote:
Sat Jan 04, 2020 11:34 am
https://www.englishchess.org.uk/monthly-grading-proposal/ wrote:
Each ungraded player will be deemed to have drawn with an 1850 graded opponent as an extra result on initial grading.
I'll take Brian's word for it that this works well for junior players new to the grading system, but what about (very) strong foreign players who enter the ECF grading system when they play in an English tournament for the first time?
A good question. I do not understand why a foreign player with a FIDE rating (a GM perhaps) but no ECF rating seems to be treated as unrated for ECF calculation purposes. A FIDE rating, based perhaps on hundreds of games, seems a better starting point than a few games and an 1850 result thrown in for good measure.

But perhaps this has all been explained previously.

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Christopher Kreuzer
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Re: New grading conversions

Post by Christopher Kreuzer » Tue Jan 14, 2020 5:12 pm

Does anyone know when the new grading list is coming out? And when is this conversion to 4-figure ELO-style ratings happening?

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