[R] Rating competitors

[Greg Snow]

One approach that is already coded in R is the Bradley-Terry model
(found in the BradleyTerry package of all places).

This could be a good place to start if you want something quick, others
have given you references if you want more detail and/or control. 


-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at intermountainmail.org
(801) 408-8111
 

-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Jeff Newmiller
Sent: Tuesday, December 26, 2006 10:54 AM
To: r-help at stat.math.ethz.ch
Subject: [R] Rating competitors

I am looking for hints on how to estimate ratings for competitors in an
ongoing pairwise competition using R... my particular area of interest
being the game of Go, but the idea of identifying ratings (on a
continuous scale) rather than relative rankings seems easily generalized
to other competitions so I thought someone might be studying something
related already.

I presume the rating of a competitor would be best modeled as a random
variate on the rating scale, and an encounter between two competitors
would be represented by a binary result.  Logistic regression seems
promising, but I am at a loss how to represent the model since the
pairings are arbitrary and not necessarily repeated often.

I have read about some approaches to estimating ratings for Go, but they
seem to involve optimization using assumed distributions rather than
model fitting which characterizes analysis in R.

Does any of this sound familiar? Suggestions for reading, anyone?

--
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Jeff Newmiller                        The     .....       .....  Go
Live...
DCN:<jdnewmil at dcn.davis.ca.us>        Basics: ##.#.       ##.#.  Live
Go...
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Playing
Research Engineer (Solar/Batteries            O.O#.       #.O#.  with
/Software/Embedded Controllers)               .OO#.       .OO#.
rocks...1k

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