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[Roger de Coverly]

This assertion made me wonder about the FIDE = 7.5*ECF+700 conversion formula, which sets 2200 FIDE = 200 ECF.

The debate on this was around 5 years ago.

http://www.ecforum.org.uk/viewtopic.php ... 4&start=15

[NickFaulks]

24 is too small a sample size for any serious statistical work.

I specifically did not claim to have proved anything. Nor do I intend to do the greater amount of work required to check whether the conversion formula is vindicated. I just wonder whether anyone better placed is doing it.

As a matter of fact, I don't accept your general point. If the average ECF grade of my small sample were 270 instead of 207, I think you would agree that the conversion formula could safely be thrown out of the window. It's a matter of degree.

[NickFaulks]

The debate on this was around 5 years ago.

Thanks, I have revisited that and will make my next post there in case anyone wishes to comment further.

This excellent post is exactly what I hoped to find.

It suggests that three years ago the 2200/200 intersect should have been more like 2175/200. My rudimentary analysis gives the impression that the disparity may have got larger rather than smaller ( to the point that it could actually matter? ). I don't propose to do any more work myself, but would be interested to see anyone else's analysis.

[Paul Cooksey]

I think that different types of competition are a significant factor on both Elo and ECF grade though. Nothing wrong with a formula for an overall average. But it may not apply to individuals like Jonathan.

I'm not active for Elo at the moment, But my experience over a long time has tended to be that if I perform to my ECF grade I gain Elo points in the 4NCL and lose them in weekend tournaments. I'd rationalised that as being a result of the different types of players attracted. The 4NCL attracts people who are not playing as seriously as they once did, whereas in an average weekend open I would expect to play one or two players who are working hard to improve their game.

Similarly I think there are hotspots where people who are improving play. Some leagues where there are a lots of juniors, weekend tournaments in London, etc. Although these are loosely connected, there are enough people playing predominately in a particular pool to prevent things evening out.

[Jonathan Bryant]

People may over/under perform against certain types of player or in particular competitions. Playing for the team on a cold winter's night after a long day at work may tend to different results than playing for yourself in a weekend tournament.

I’m quite sure that you are right. However, it’s not relevant to the situation that I’m describing - because I’m talking about differing rating/grading performances for the same set of games (i.e just weekend tournaments).

I looked at the 24 ENG players with active ratings from 2185 to 2215 who have ECF grades. They have an average grade of 207, quite a serious disparity. Has any proper work been done on this?

Don’t know, but your finding will surprise precisely nobody who plays regularly in London and the South East.


When I’ve discussed this before - here and elsewhere - I’ve been told that the disparity balances out in some areas. That is, one is just as likely to find a person with an ECF far higher than the 'equivalent elo' as the other way around. Seem to remember somebody arguing this was his experience for 4NCL games, for example.

May or may not be true for all I know. What I do know for certain is that it is not at all true of the tournaments in which I play. My elo being about 150 points lower than the supposed converted ECF being not at all untypical for the opponents that I meet.

There was a time - at the start when half of my elo rated games were played abroad - when my elo and ECF conversion was pretty much identical.

[Jonathan Bryant]

Nothing wrong with a formula for an overall average. But it may not apply to individuals like Jonathan.

Totally agree with your first sentence. Don’t dispute your second sentence either, except perhaps that it makes me sound like an outlier. Some kind of statistical oddity. I don’t think that’s at all true though. On the contrary, I think my elo-grade issue is entirely normal for the population of chessers down my way.

Not that I think there’s anything in particular can be done about it. Except for simply ignoring your opponent’s elo and looking at their ECF instead if you want some kind of idea of their playing strength.