Yet More Deflation

[Tim Spanton]

I see from analysis of the new ECF grading list at http://www.sccu.ndo.co.uk/grad.htm that the average standard grade has fallen from last year. Time for another regrading?

[Alex Holowczak]

I think the far more important statistic is at the top of the page: Players active and players published have decreased again, but there has been no noticeable drop in the number of graded games, a number which has stayed roughly constant since 2005. By contrast, rapidplay activity has gone the other way. Is this through having more opportunities to play rapidplay?

[Sean Hewitt]

I see from analysis of the new ECF grading list at http://www.sccu.ndo.co.uk/grad.htm that the average standard grade has fallen from last year. Time for another regrading?

Nope. The average standard grade, in isolation, is a meaningless measure.

[IanDavis]

I think the far more important statistic is at the top of the page: Players active and players published have decreased again, but there has been no noticeable drop in the number of graded games, a number which has stayed roughly constant since 2005. By contrast, rapidplay activity has gone the other way. Is this through having more opportunities to play rapidplay?

Does the mean expand with the total population, as it has been shown to do with FIDE grades?

[John Upham]

Does the mean expand with the total population, as it has been shown to do with FIDE grades?

Forgive my denseness but how would an arithmetic mean "expand"?

Are you refering to the standard deviation or some other quantity?

[IanDavis]

Does the mean expand with the total population, as it has been shown to do with FIDE grades?

Forgive my denseness but how would an arithmetic mean "expand"?

Are you refering to the standard deviation or some other quantity?

I was thinking that its magnitude expanded, but perhaps I should have used another verb. It was something I picked up on from reading articles like these http://www.chessbase.com/newsdetail.asp?newsid=6401 , although they were published on chessbase, so perhaps I should have disregarded them completely.

[E Michael White]

Time for another regrading?

There will probably need to be more quantative easing exercises for the graders but not every year.

In the 1980/90s etc graders assumed that junior increments would solve the problem of deflation but disregarded the other sources of deflation eg the correlation between more active players and grade improvement. The current junior fix does the same thing a different way.

I dont think its been mentioned before but Swiss events with an odd number of players also cause deflation and spread of grades, by small amounts which accumulate.

Some baby boomers born 1945-1950 seem to be returning to play more chess; this is likely to have a short term inflationary effect and may make the current grading fix look more effective than it is in curing deflation.

[Sean Hewitt]

I dont think its been mentioned before but Swiss events with an odd number of players also cause deflation and spread of grades, by small amounts which accumulate.

Hi Michael. That's interesting. Can you tell us why that is?

Some baby boomers born 1945-1950 seem to be returning to play more chess; this is likely to have a short term inflationary effect and may make the current grading fix look more effective than it is in curing deflation.

Can you tell me why this is likely to be inflationary? I can't figure it out this early in the morning!

[Roger de Coverly]

disregarded the other sources of deflation eg the correlation between more active players and grade improvement.

Could you expand this? We know that more active players have a higher average grade than less active players. An obvious conclusion is that if you play a lot, then you get better. I don't think that players playing 5 games a year have much impact on those playing 30 or much more

both

because you are less likely to meet them in an event ( because they don't play much)

and

because the effect of one individual game is reduced for the more active players.

Some baby boomers born 1945-1950 seem to be returning to play more chess; this is likely to have a short term inflationary effect and may make the current grading fix look more effective than it is in curing deflation.

Do you have an opinion about changes in skill standards? Take two players who were about equal graded in the 1970s. One retired then and has recently returned but hasn't updated their knowledge. The other has played continuously. Do you think they will both have about the same grade playing today?

[IM Jack Rudd]

The more games a year you play, the less impact any individual result has on your ECF grade. If I play someone of my own grade and beat him, where I play 100 games a year and he plays only 50, this will have cost him 1 grading point but gained me only ½ a grading point.

[Paul McKeown]

The more games a year you play, the less impact any individual result has on your ECF grade. If I play someone of my own grade and beat him, where I play 100 games a year and he plays only 50, this will have cost him 1 grading point but gained me only ½ a grading point.

And more active players are likely to be stronger than less active players, therefore ....

[Sean Hewitt]

The more games a year you play, the less impact any individual result has on your ECF grade. If I play someone of my own grade and beat him, where I play 100 games a year and he plays only 50, this will have cost him 1 grading point but gained me only ½ a grading point.

And more active players are likely to be stronger than less active players, therefore ....

Absolutely right, although this has been well known for some time.

[Roger de Coverly]

If I play someone of my own grade and beat him, where I play 100 games a year and he plays only 50, this will have cost him 1 grading point but gained me only ½ a grading point.

and vice-versa of course so the direction of the effect is neutral unless there's a strong correlation between activity and result. I doubt that playing 100 against 50 makes any real difference.

More to the point is that the active players mostly play each other, so it doesn't have much effect on the most active players as to what grade the inactive players (5 a year) have.

[Brian Valentine]

Paul McKeown wrote:
IM Jack Rudd wrote:
The more games a year you play, the less impact any individual result has on your ECF grade. If I play someone of my own grade and beat him, where I play 100 games a year and he plays only 50, this will have cost him 1 grading point but gained me only ½ a grading point.

And more active players are likely to be stronger than less active players, therefore ....

Absolutely right, although this has been well known for some time.

While I agree with Sean about his earlier remark that one shouldn't use just one statistic, I'm not sure this concept has much affect. The point is that if both players repeat their activity the next year Jack will contribute 100*.5 points = 50 into the rating pool to be redistributed by results, whereas his opponent will place 50*1 points =50 into the pool. Hence deflation explained by this idea only occurs if activity alters.

[Paul McKeown]

My comment was only making clear the implication: it certainly doesn't endorse the view that this is the only factor causing the gradings curve to drift or deform. I do not believe for a second that the regrading was necessary or justified.