From: genetic+@pitt.edu (Dr. Dave)
Newsgroups: rec.sport.baseball
Subject: Re: Cecil signs :-( :-( :-(
Date: 25 Jan 93 13:59:21 GMT
Organization: Department of Industrial Engineering

Thus spake mjw@Xenon.Stanford.EDU (Michael Wolverton):
[about stuff I said]

>But I think you're using replacement value in this car analogy: you
>evaluate your car by looking at what it would cost you to perform its
>function IF YOU DIDN'T HAVE THE CAR.

But you can only take the car example so far, because I'm not competing
against other drivers (except at rush hour).  It wasn't meant to be a perfect
analogy; just an illustration that there can be more than one kind of "value".

>You do the same with baseball players: look at what you get when you
>*do* have the player, and look at what you'd get if you *didn't* have
>the player.  Subtract the second from the first, and that's your
>player's value.  

...unless most of the league is *better* than what you do have.  In which case
he is *not* helping you win, no matter how far above "replacement level" he
is.  Players who take away wins and add losses to your team have (it seems to
me) negative use value.

>>Now, I claim that this applies to baseball players.  A player's use value
>>is what he does to your chances of winning when he plays.  Since winning is
>>defined as scoring more runs than your opponent does, this value consists 
>>solely in how much he contributes to your run differential.

>I'm with you up to here.

Good; that was the controversial part :-).  The rest is easy...

>>Run differential
>>is not a function of who the worst player in the league is, but rather of who
>>is actually playing in the league.

>Here I'm just not sure I understand you.  Isn't the worst player in the
>league "actually playing in the league"?  Do you mean "getting lots of
>playing time in the league"?  

No, I meant "a function of who *all* the teams are playing regularly".
That's what determines the (expected) W/L records for the teams, right?
How many games the Mets win in '93 will be a function of how well their
players do, and how well all the other teams' players do, *regardless* of
where "replacement level" is for the league.  W/L records depend directly
on the average league performance, and not on the minimum.

>>Thus, average value at a given position
>>is the relevant baseline for use value.
>
>This is where I lose you.  I don't see how this sentence follows
>logically from anything you've said previously.  *Any* player
>contributes (positively) to your run differential, provided he's
>better than what you'd have if he wasn't there.  

No, he doesn't.  If you have an entire team of replacement-level players,
you'll lose 120 games.  The sum (use) value of all your players is thus
about -40 games.  If they're all about the same, that means they *all* have
negative value.  *Very* negative.

>No team can fill
>their roster with only better-than-average players, 

Wanna bet?  The '27 Yankees?  The '09 Cubs (or whatever year that was)?
The '61 Yankees?  Bench doesn't count, unless somebody gets hurt, because
it's who actually plays that determines how many runs you score and allow.
I think it's obvious that there are occasional teams that are at least 
average at every position.  And even if there weren't, it wouldn't affect
the argument at all.  

>and any team
>improves itself by replacing its really bad players with better -- but
>still below-average -- players.

I don't know where this came from, but I disagree.  

>I've used this example before, but it's still a good one: look at the
>bulk of last year's A's starting pitching -- Stewart, Darling, Moore,
>Witt, Slusarski.  All below average.  Yet I really believe that a
>season-ending injury to any of them (except Slusarski) would've hurt
>the A's.  They simply didn't have anyone better to turn to.  Still,
>with this staff o' stiffs, they won the division.  Stewart et. al. had
>negative value if you use league average as a baseline, but they still
>contributed positively to a division-winning club in reality.

No, they just weren't negative *enough* to outweigh the positives from the
offense.  Failing to be even worse than you are does not constitute being
a contributing factor toward winning.  Had the A's been able to replace these
guys with average pitchers, they would have won more.  That's another way of
saying that the league in general was getting something positive from its
pitchers that the A's were *not* getting from *their* pitchers.

>>Replacement
>>level tells you how badly your team's winning percentage would fall if all the
>>shortstops in your organization were killed by a freak meteor shower, so that
>>you had to go out and sign AAA players and released major-leaguers.  
>
>It's not quite like this.  You evaluate baseball players in the same
>way you evaluated your car above and in the same way you'd evaluate
>anyone or anything -- by figuring out the costs/benefits of having
>him/her/it versus not having him/her/it.

That's how you would do it if baseball weren't competitive.  But the basic
nature of baseball is that how much you win depends *solely* on the relative
abilities of your players vs. everybody else's players.  Not on your players
vs. AAA players or released major leaguers.

Thought experiment:  suppose everybody else's starting 9 suddenly got much
much better, but yours didn't, and the talent not currently in the majors 
stayed the same.  Clearly, your players are suddenly much less valuable than
they used to be, because they will win many fewer games than they used to.
But replacement level HAS NOT CHANGED; average level has.

-- 
       David Tate        |"Something there is that doesn't love a wall,
 dtate@unix.cis.pitt.edu | That sends the screaming liner over it 
 Prof. of Story Problems | And spills the bleacher-dwellers from their seats."
 Member ORSA, TIMS, SABR |  	"Fenway Wall", Robert Frost          
Newsgroups: rec.sport.baseball