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Subject: Re: K Value Changes

Author: Robert Hyatt

Date: 11:22:39 03/18/99

Go up one level in this thread


On March 18, 1999 at 11:12:16, Andrew Dados wrote:

>
>On March 18, 1999 at 10:23:23, KarinsDad wrote:
>
>>On March 17, 1999 at 22:21:09, Robert Hyatt wrote:
>>
>>>On March 17, 1999 at 17:43:21, KarinsDad wrote:
>>>
>>[snip]
>>>>Robert,
>>>>
>>>>Are you saying that the servers do not decrease the ratings changes (i.e. halve
>>>>them just due to the fact that a higher rated player is playing) for the higher
>>>>rated players?
>>>>
>>>>If so, this is strange and disturbing.
>>>>
>>>>KarinsDad :|
>>>
>>>
>>>No... the Elo system has a 'max change' paramater K, that seems to be set to
>>>32 for most places.  And that works well in that the most your rating can change
>>>with any one game is 32 points.  But it is proportional to the rating difference
>>>between you and your opponent.
>>>
>>>Other servers use a smaller K (chess.net for example) as suggested by the
>>>'glickman' proposal for rating calculation.  If you reduce K, then you reduce
>>>the maximum rating change delta.  and you limit rating 'swings'...
>>
>>Robert,
>>
>>As I'm sure you are aware, the USCF modifies the K for higher rated players.
>>
>>For players 2100-2399, the change is multiplied by 0.75.
>>For players 2400+    , the change is multiplied by 0.5.
>>
>>It would seem logical for the chess servers to do something similar since you do
>>want some more major level of stability at the higher ratings than you need at
>>the lower ratings.
>>
>>Do any of the servers publish their K values and potential modifications to it?
>>
>>Thanks,
>>
>>KarinsDad :)
>
>    Go to fics and type 'help glicko' for highly detailed explanation how K is
>obtained there...
>does it make practical sense - that's a different story...
>-Andrew-


I don't know if FICS still uses the Glicko system, but the last time I looked,
they did, and it was _far_ better, IMHO.  In that it tended to limit big rating
swings..



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