From: genetic+@pitt.edu (Dr. Dave)
Newsgroups: rec.sport.baseball
Subject: Re: NL ROY: More Fuel for Debate
Date: 1 Oct 92 19:06:46 GMT
Organization: Department of Industrial Engineering

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

>In article <6551@blue.cis.pitt.edu.UUCP> genetic+@pitt.edu (Dr. Dave) writes:
>>Thus spake claudius@leland.Stanford.EDU (Nelson Lu):

>>But that's not true, either.  You're saying that one Barry Bonds would
>>contribute just as many runs per out in an average lineup as he would when
>>surrounded by other Barry Bondses, and that's just plain false.
 
>But isn't that also a problem with MLV?  

It's precisely the problem that MLV was designed to get around.

>Brett Butler will contribute different number of runs when
>surrounded by a lineup of Pete O'Brienses than when surrounded by Jeff Husons.
>But you still have to come up with just one number for Butler.

Right.  So, I pick a reference lineup (which could be the Dodgers' actual
lineup, if I want to know how many runs I can expect out of Butler this year,
or could be the Padres' lineup if I'm the Padres' GM and am thinking of getting
him by trade, or could be a league-average lineup if I'm just trying to compare
Butler's general value to that of other players around the league).  Then I
look to see how many more runs that lineup can be expected to score with
Butler than they would with an average CF.

>>Normalizing by outs consumed does *not* correct for the interaction effect
>>in RC, by which a player with balanced OBP and SLG gets credit for batting
>>with lots of runners on base *and* for converting them efficiently, *and*
>>for being driven in at a very high rate.  In a real lineup, there wouldn't
>>be that many runners on base to convert, and the following batters wouldn't
>>convert the player in question as frequently, even if the player in question
>>put up exactly the same numbers.  RC overestimates the *marginal* value of
>>individual OBP and SLG, due to this self-compounding effect.
>
>I disagree to a small extent.  Why should we penalize Eddie Yost-type
>players just because GMs fail to see their value offensively?  A player who
>has a high OBP and high SLG should not be penalized by the fact that teams
>stock their roster with low-OBP/high-SLG players.

No, you've missed the point of my objection again.  I'm saying "If we want to
predict how many more runs Eddie Yost will cause the Senators to score, over
what an average offensive player would give them, it makes no sense to ignore
the fact that Yost will be batting in the Senators' lineup, and pretend that
he'll be batting in a lineup of Eddie Yosts."  That's not *penalizing* Yost,
it's just trying to be accurate.

Teams stock their rosters with average players, on average.  This is a
tautology.  To figure out what a specified player gives you, you need to
know how his skills will contribute at the margin in an average lineup.
If you'd rather know how he'd do in a particular team's current lineup,
you can do that with MLV as well.  But why should you care how many extra
runs he would contribute to a team that's much better than any real team?
What do you learn from that?

I'm not penalizing anybody; I'm compensating for RC's tendency to *overvalue*
good hitters' performances by placing them in the context of a team of good
hitters.

>>>2.	MLV does not account for the effects of the running game or for a
>>>	player who grounds into double-plays a lot.
>>
>>DPs, no.  Stolen bases can be added in as 0.3*(SB-2*CS) added to TMR.
>
>But isn't there a point of diminishing returns for stolen bases?

Possibly.  It wouldn't be too hard to do technical-version RC projections for
teams, and to look at individual player impacts on these.  The idea's the
same.

>>>3.	Since you use league averages to derive MLV's, it gives no indication
>>>	of how much value a below average player might have.
>>
>>I disagree.  It tells you how many fewer runs you will score with this guy
>>than you would with a league average guy.  What other measure of value did
>>you have in mind?
>
>What I mean is...
>
>Eric Karros has some value this year, despite being below average.  How
>much is that value?

What value did he have?  He had some value in the sense that he was better
than just playing 8 guys, or playing me at first base.  But, in the sense that
other teams were getting more from their first basemen, he was *not* helping
the Dodgers win.

The baseline, as I see it, is a .500 winning percentage.  If everybody had
the same talent, then everybody would expect to win half their games (though
of course random variation would cause a more-or-less symmetric spread around
81-81 records).  The way you win more games than you lose is by having above-
average performances.  If a player is below average, he's helping you lose,
relative to what other players at that position are doing.  If Karros's park-
adjusted numbers are below average, then he's helping the Dodgers lose, and
his value should be measured accordingly.

>By using MLV, the *more* Karros plays, the more he gets punished by getting
>more and more negative MLV.

That's because he's costing his team more and more games, relative to other
first basemen, and other first basemen are the only relevant yardstick.



-- 
       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