From: genetic+@pitt.edu (Dr. Dave)
Newsgroups: rec.sport.baseball
Subject: Re: NL ROY: More Fuel for Debate
Date: 29 Sep 92 17:17:55 GMT
Organization: Department of Industrial Engineering

Thus spake claudius@leland.Stanford.EDU (Nelson Lu):

>In article <6416@blue.cis.pitt.edu.UUCP> genetic+@pitt.edu (Dr. Dave) writes:
>
>>RC/27 refers to what an idealized team of 9 copies of these players would
>>do.  There is NO WAY, none, to translate those numbers into estimates of
>>their actual value as one of nine players in a real lineup, even an
>>average one.  Ditto for an alleged "replacement level" player.  You can't 
>>subtract one player's RC/27 from another's to find the difference, because
>>RC/27's aren't additive.

>But we aren't adding anything here.

Subtraction is adding a negative number.  Differences are only meaningful if
the thing you're taking the difference of is additive.  (Or, more accurately,
differences can only be extrapolated linearly if the functions you're taking
the difference of are linear.)

>Besides, just because teams like to stock on low-OBP/high-SLG players doesn't
>mean that that is the way that teams should be run.

I have no idea what this has to do with my objection.

>Besides, if a lineup will score 5 runs a game, and another will score 4,
>isn't there a 1-run difference between these lineups?

Lineups, yes.  People, no.  If 9 Barry Bondses would score 12 runs per game,
and 9 Terry Pendletons would score 7 runs per game, is Barry Bonds worth 5
extra runs per game over Pendleton?  Of course not; Bonds's team doesn't even
score 5 runs per game.  RC/27 multiplies Bonds's offensive advantage times
itself, 9 times over.  What does that say about actual player values to real
teams?  Nothing.  It is, at best, an index for ranking players by how much you
might want to build an offense around them.

>>Extreme example:  consider two players, me and Frank Thomas, in the context
>>of Gary Huckabay's SVBL league.  Frank would have an RC/27 of about 80, while
>>I would have an RC/27 of about 0.1.  However, if you consider what happens
>>when you replace Huckabay with me or Frank, this alleged 80 run difference
>>per game vanishes.  

>And a big, BIG problem with your MLV, Dave, is that it is *very* difficult to
>calculate.  

That's why we have our Little Digital Friends.  Nothing says that accurate
estimates of value have to be easy to find...

>*Ideally*, you can't tell the whole story from OBP, SLG, or
>whatever stat, but rather, you should be able to get the records of who made
>an out on the basepaths not shown by stats, who advanced an extra base, etc.,
>and figure them in the RC model.  *But* we don't have those available.  What
>you lose by using MLV is accessability.

MLV only uses BA, OBP, SLG, and PA.  Hardly rocket science.  Frankly, it's
more accessible than the later versions of RC, given that you have to code
both of them up at some point.

>Besides, the example you gave above is way too extreme to be a possibility.
>These are major league players we are talking about, after all.  

All right, look at Bonds and Pendleton, then.  The point stands.  In fact,
the point stands for any two players you care to name.  

>And I don't
>think that MLV will be able to derive the Thomas effect in your example
>correctly, either.

Wanna bet?  (Why don't you think so?)


-- 
       David Tate        |"Out of the dugout endlessly swinging,
 dtate@unix.cis.pitt.edu | Out of the manager's throat, the sound fundamentals,
 Prof. of Story Problems | Out of the six-month season..."            
 Member ORSA, TIMS, SABR | 	Walt "Lefty" Whitman