Converting Scottish to English grades

General discussions about ratings.
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Jon Mahony
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Converting Scottish to English grades

Post by Jon Mahony » Thu Jun 25, 2015 11:57 am

Hi All,

I need to convert a Scottish grade of 1503 into an ECF equivalent grade. Is there a formula for this?

Thanks
"When you see a good move, look for a better one!" - Lasker

Roger de Coverly
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Re: Converting Scottish to English grades

Post by Roger de Coverly » Thu Jun 25, 2015 12:34 pm

Jon Mahony wrote: Is there a formula for this?
You might wish to read this
http://www.chessscotland.com/grading/outside.htm

from which
With effect from 1st January 2014: ECF x 7.5 + 700 = FIDE (FIDE - 700) / 7.5 = ECF

CS will continue to use *10+180.
So if you apply the ECF approach, you get 107. Using the Chess Scotland approach 132.

The revaluation of ECF grades moved the "average" player from the 110 to 125 range up to the 125 to 140 range. Chess Scotland would regard your player as just below average, while the ECF conversion would treat him as well below average.

Alex McFarlane
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Re: Converting Scottish to English grades

Post by Alex McFarlane » Thu Jun 25, 2015 12:36 pm

I have correspondence which states that the ECF does not recommend a conversion factor. The FIDE one is not intended for this purpose (or for Welsh grades). I pointed out that I would expect most organisers to use the FIDE conversion but did not get a satisfactory answer.

The OFFICIAL Chess Scotland conversion from ECF is x10 +180.

Using the inverse gives (1503-1800/10=1323/10=132.

Scarborough uses the Scottish formula as, I believe, does Blackpool.

Hope this helps.

I see Roger has added to my answer.

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Jon Mahony
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Re: Converting Scottish to English grades

Post by Jon Mahony » Thu Jun 25, 2015 12:42 pm

Thanks both, most helpful :)
"When you see a good move, look for a better one!" - Lasker

Roger de Coverly
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Re: Converting Scottish to English grades

Post by Roger de Coverly » Thu Jun 25, 2015 12:59 pm

Alex McFarlane wrote: Scarborough uses the Scottish formula as, I believe, does Blackpool.
Both have years of experience of the participation of club strength Scottish players and how they compare to their English counterparts. If you look for conversions between two well established and universal national rating or grading systems, checking the equivalence of values in the middle where the most players are found is a valid approach.

Brian Valentine
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Re: Converting Scottish to English grades

Post by Brian Valentine » Thu Jun 25, 2015 2:24 pm

Jon,
The reason the ECF make no recommendation is that the situation is complicated. The conversion depends on what you want the conversion for.
The ChessScotland conversion (*10+180) gives a higher Scottish equivalent than most observers might expect. This has the effect of putting the English in higher rated sections than might be appropriate when playing in Scotland. If one works the other way using that formula then the Scots get a relatively easy ride when playing in England.
If you are looking to assess your performance against this player then *7.5+700 is as good as anything. If you are looking to put him in the right section in a club competition (for instance) then the reverse of the Scottish grade is not the one to use.

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Jon Mahony
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Re: Converting Scottish to English grades

Post by Jon Mahony » Thu Jun 25, 2015 3:49 pm

Brian Valentine wrote:Jon,
The reason the ECF make no recommendation is that the situation is complicated. The conversion depends on what you want the conversion for.
The ChessScotland conversion (*10+180) gives a higher Scottish equivalent than most observers might expect. This has the effect of putting the English in higher rated sections than might be appropriate when playing in Scotland. If one works the other way using that formula then the Scots get a relatively easy ride when playing in England.
If you are looking to assess your performance against this player then *7.5+700 is as good as anything. If you are looking to put him in the right section in a club competition (for instance) then the reverse of the Scottish grade is not the one to use.
Hi Brian

I have had a Scottish player contact me in regard to playing in the Leeds congress, but he only has a Scottish grade, and he wanted to know which section he would be eligible to enter. I will have to have a chat with the other organisers before I make a final decision. He's out of the Minor for sure, but with Alex's conversion can get in the Inter if he so wishes.
"When you see a good move, look for a better one!" - Lasker

Alex McFarlane
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Re: Converting Scottish to English grades

Post by Alex McFarlane » Thu Jun 25, 2015 4:39 pm

Brian Valentine wrote:This has the effect of putting the English in higher rated sections than might be appropriate when playing in Scotland. If one works the other way using that formula then the Scots get a relatively easy ride when playing in England.
Brian,
Please explain this statement. Roger's calculations show the exact opposite of what you continue to claim.
Surely for the 1503 the Scottish conversion puts him in a higher section than your suggested "ECF" one. In what way is that giving him an easier ride?
I've raised this with you before but gave up!

The CS conversion was based on a comparison of everyone who had a CS and ECF grade at the time it was formulated. You admit that no research was done in England. Are you in a position therefore to make the outlandish claim that you do?

If you want another example look at my CS grade. Convert it with your formula and then compare to my ECF rating!!

Brian Valentine
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Re: Converting Scottish to English grades

Post by Brian Valentine » Thu Jun 25, 2015 5:01 pm

Alex,
You are quite right, I am wrong - Roger's calculations are correct and I've managed to invert the implications.

It would not be true to state that no research has been done in England. Officials in Scotland are in a better position to do such comparisons as they would have access to the Scottish ratings. The ECF team would not presume to have superior skills or knowledge. Currently in the limited circumstances where graders need to, we assume Scottish Ratings are equivalent to FIDE.

Alex McFarlane
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Re: Converting Scottish to English grades

Post by Alex McFarlane » Thu Jun 25, 2015 5:43 pm

Thank you Brian.

You may now wish to alter some of the comments you made in your email correspondence with me. You inverted the implications then as well!

As I have pointed out to you before the ECF/FIDE conversion simply does not work at the bottom end for Scottish players. It is a great pity that the ECF continues to use it for players below 1500 and probably a higher figure.

If you want access to the Scottish figures I'm sure our grader will be only too happy to make you an "area grader" with access.

Brian Valentine
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Re: Converting Scottish to English grades

Post by Brian Valentine » Thu Jun 25, 2015 6:18 pm

Alex,
It doesn't help Jon or anyone else to continue this discussion in public.

The ECF only uses this conversion for Games Played Abroad, where ECF members play in Scotland and play players without either an ECF grade or a FIDE rating. It has been used in just one half-game in 2015. If people need help on conversion issues then I can be contacted at [email protected].

Brian Valentine
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Re: Converting Scottish to English grades

Post by Brian Valentine » Thu Jun 25, 2015 6:22 pm

Hi Brian

I have had a Scottish player contact me in regard to playing in the Leeds congress, but he only has a Scottish grade, and he wanted to know which section he would be eligible to enter. I will have to have a chat with the other organisers before I make a final decision. He's out of the Minor for sure, but with Alex's conversion can get in the Inter if he so wishes.[/quote]

Jon, I have nothing better to give than to follow Alex's observations about Blackpool and Scarborough. At least you then have precedents

Alex McFarlane
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Re: Converting Scottish to English grades

Post by Alex McFarlane » Thu Jun 25, 2015 7:13 pm

Brian Valentine wrote: It doesn't help Jon or anyone else to continue this discussion in public.
Agreed, which is why I referred you back to our email conversation. I assumed that you would continue it having realised the wrong assumptions you made in it. I look forward to hearing from you by email.