[R] Rating competitors

[Jeff Newmiller]

Spencer Graves wrote:
>      Have you considered Bradley-Terry models?   RSiteSearch("bradley", 
> "functions") just returned 31 hits for me.
>      Hope this helps.      Spencer Graves

Thanks to everyone who responded... this was very helpful. I have a bit of
reading and investigation to do.

I think the Bradley-Terry model is going to be sufficient for my purposes,
if I can figure out how to model handicaps.  The eba library mentioned by
Kubovy seems more complex than what I need now, but it does look interesting
and if I can obtain a copy of the Tversky paper I will read it.  The SIS
link mentioned by Berry didn't seem to have much, but the article on
Bridging Different Eras in Sports is quite interesting.

> Jeff Newmiller wrote:
> 
>> 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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