From: "Daniel M. Toebbens" <toebbens <at> HMI <dot> DE>
Date: 12 dec 2002
Subject: Re: Elo ratings and grades

On Thu, 12 Dec 2002, Stouten, Pieter [R&D/0467] wrote:
> --- Hugo Hollanders <H.Hollanders <at> MERIT <dot> UNIMAAS <dot> NL> wrote:

> > Furthermore, there is NO link between a player's current elo-rating
> > and his playing grade.
> > [...]
> > If one thinks otherwise, a close look at the current elo-list proves
> > that there is no link between dan/kyu-grade and elo-rating. And this
> > can also not be achieved, unless de-promotions would be introduced
> >
> Looking at the Elo list, you will notice significant correlation between
> ratings and grades. In fact, I hope that Asle can determine the statistical
> correlation when he gets back from vacation.

I think he meant that there is no strict relationship between the current
Elo and the grade. Of course there is a strong correlation between grade
and Elo (though it is not linear, more like exponential growth). However,
if one looks at i.e. the 2 dan grade, the corresponding elo points reach
from 1546 to 2118!



> > Dan- and kyu-grades reflect a past "best" performance,
> > and as such these will always on average overestimate a player's
> > strength. To put it more simply, a dan- or kyu-grade is more of
> > an honorary nature, [...]
> >
> Indeed more simply put, but also inaccurately. The Elo-based grades are in
> no way honorary. They are tough to get titles that are exclusively based on
> actual sustained (!) peak performance. Elo ratings predominantly reflect
> current strength; grades reflect peak performance. I think there is a place
> for both, and I think we should take both seriously. Therefore, FESA and
> USSF need to decide how they want to do that. And that may very well include
> accepting NSR grades.

This argument only holds, if you see the Elo-based grades as the 'real'
ones. In that case those given for tournament or club performance are a
problem to the system. Not to speak of those 'honorary' grades given for
other merits. But, since those other grades exist and, as far as I
understood, have existed even before the Elo system: Is not the whole
concept of purely Elo-based grades flawed from the begin? Personally, I
have no problem in seeing a dan grade given for great merits due to the
promotion of shogi as as valueable as one achieved through the Elo system.

That's just the two cent of a still-not-strong newcomer to the shogi
world, of course.


Daniel Többens