From: sloan@cis.uab.edu (Kenneth Sloan)
Subject: Re: Inflation in ELO's system
Organization: CIS, University of Alabama at Birmingham
Date: Thu, 8 Oct 1992 16:01:51 GMT

In article <4051@cvbnetPrime.COM> fdeming@cvbnet@prime.com (Frank Deming {x6088}) writes:
>...
>The problem with what you have presented is that many of the beginning and
>average players leave the game, in greater numbers than the strong players.

But the relevant question is: do these beginning and average players
leave the game with a higher or lower rating thant their initial
*established* rating?  

Let's take a few examples:

Player 1: plays in 2 tournaments, and never returns

Player2: plays in 5 tournaments, receiving an initial established rating
of 1200.  Continues to play for 2 or three more tournaments, raising his
rating to 1250 - and then gives up.

Player 3: playes informally for a long time, and gets quite good.
Enters USCF play and receives an initial established rating of 1800.
Plays for 50 years, acheiving a peak rating of 2350 - after which the
ravages of time reduce his skill and his rating drops to 2100.  

As a result of these players entering and leaving the pool:

                        Player 1    Player 2    Player 3
rating points created      0          1200       1800
rating points removed      0          1250       2100
---------------------    ---          ----       ----
net effect                 0           -50       -300

Player 1 never causes the system to mint new rating points, but he
doesn't remove any from the pool.  The other two (fairly typical)
careers have the net effect of removing rating points from the pool.

Of course, we might also have:

Player 4: enters USCF play after years of study in Bolivia, receiving an
initial established rating of 2299.  Discovers Bill Goichberg, and
sandbags his rating down to 2100.  Wins $10,000 every year at the World
Open, and spends every weekend the rest of the year getting his rating
back down to 2100.  Eventually retires to Aruba with his winnings.

Player 5: Player 4's brother.  Smarter than his brother, he sandbags
during his Provisional Rating days, and enters with an initial
established rating of 986.  Wins a different section in a Goichberg
tournament every year - moving up as slowly as he can, and doing lots of
sandbagging along the way.  Retires with a rating of 2399 and *buys*
Aruba with his winnings - taking along Goichberg as his personal body
slave. 

Player 4 contributes 199 rating points to the pool when he leaves, along
with a few $$.

Player 5 removes 1413 rating points, and lots more $$.

Of course, every once in a while, you get:

Player 6: plays for 15 years in Bolivia, developing a completely new
style and several TN's.  Wins everything in his first 5 tournaments and
gets an initial established rating of 2650.  This gets the attention of
the local masters, who study his games and unravel his novelties.  They
then beat him back down to his natural level of 2150 - at which point he
moves to England, hoping to do it again before Inside Chess does a story
on him.

Player 6 removes 500 points from the pool - contributing to rating
inflation.

The only question left is:  how many of each kind of player are there?
What is the *net* gain or loss of rating points?

-- 
Kenneth Sloan                   Computer and Information Sciences
sloan@cis.uab.edu               University of Alabama at Birmingham
(205) 934-2213                  115A Campbell Hall, UAB Station 
(205) 934-5473 FAX              Birmingham, AL 35294-1170