From: dtate+@pitt.edu (David M Tate)
Newsgroups: rec.sport.baseball
Subject: Re: RP/PA for AL and NL (More bogus RP stats)
Date: 21 Jul 92 16:16:17 GMT
Organization: Factors of Ys, Inc.

In article <BrqtJn.w0@undergrad.math.waterloo.edu> djohnson@cayley.waterloo.edu (David Johnson) writes:

>In article <3388@blue.cis.pitt.edu.UUCP> dtate+@pitt.edu (David M Tate) writes:

>>In article <Brp3LH.LEo@undergrad.math.waterloo.edu> djohnson@cayley.waterloo.edu (David Johnson) writes:

>>>If you are looking for a good denominator how about total team runs.  This
>>>will show the players value to the team.  

>>!?  What makes you say that?

[massive deletion]

>>But let's get back to the original premise.  Why do you think that "% of team
>>runs driven in" tells you anything useful about a player?  Two identical 
>>players with identical stats in identical situations could still look very
>>different using this measure--all it takes is for one of them to have the
>>bottom of the Astros order in his lineup, and the other the bottom of the
>>Tigers' order.  How is this an individual measure?  When the noise is larger
>>than the signal, it's time to look elsewhere for measures.

>This stat shows the players value to the team.  

I heard you the first time.  I just don't see how you reached this odd
conclusion.  Or do you have some weird definition of "value" that you
aren't sharing with me?

>If Joe Carter played for
>California he will not likely get as much of an opportunity to drive in
>runs and will be driven in less as well 

True.

>but dividing it by the teams total
>runs this factors in the whole teams inability to drive in runs.  

No, what it does is tell you approximately where Joe Carter ranks among
Angels players in terms of being awarded RBIs.  It *prevents* you from
making any comparison with players on other teams, since the context of
playing on the Angels has nothing in common with, say, the context of
playing for the Blue Jays.

What fraction of the '27 Yankees' runs did Babe Ruth drive in?  Compare that
with Nate Colbert on the Padres of the early '70s.  Was Nate Colbert more
valuable than Babe Ruth?

The problem with this "more valuable to his team" thing is that you give a
player credit for having rotten teammates, which is silly.  Colbert may or may
not have contributed more toward winning than other Padres batters, but there's
no way that the Pads wouldn't have done much better with Babe Ruth instead.
Who cares what % of a team's runs come from player X?  

>Lets put
>Carter on a lousy offensive team and he gets 90 RBI hits .280 30 HR and 
>scores 50 runs.  Does this make him a worse player than if he had 105 RBI
>and 65 runs scored with 30 HR and .280 average on a good hitting team.  Lets
>say the first team scored 600 runs and the second team scored 750.
>
>     Team #1 - RC = 110
>               Players Value =  110/600 = 0.183
>     Team #2 - RC = 140
>               Players Value =  140/750 = 0.186

I think you mean "RP", although that name is pretty objectionable, too.

The point is not that it makes him a worse player; the point is that it
makes him *the same* player, whichever team you put him on.  Regardless of
the RBI and R totals that his team makes out of him.

(Aside: rather than thinking of R's and RBI's as rates at which a particular
 player produces runs, it's far more enlightening to think of them as rates
 at which the *team* converts this player's abilities into team runs...  As
 such, adjusted for player OBP/SLG/SB/CS, they become a nice team measure of
 offensive efficiency.)

(Aotherside: why am I arguing with someone who thinks you can tell how good
 a player is from his batting average, HR totals, runs scored, and RBIs?)

>This shows that the players are closer to being equal which is what it should
>be since one is on a bad team and one is on a good team.

So?  Divide them both by walks allowed by the pitching staff and that will
be "closer to being equal", too.  You have to pick a normalization factor 
that makes sense for what you're trying to measure.  Team runs do not count
the degree of RBI/R opportunity that Carter gets, so dividing by them doesn't
give you his ability as an RBI/R man, much less his value toward team scoring.



-- 
       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