From: cmk@athena.mit.edu (Charles M Kozierok)
Subject: defensive measures of performance (was -- Re: Lists: The Best Players In Baseeball)
Keywords: RF, DA, ???
Organization: Massachusetts Institute of Technology
Distribution: na
Date: Fri, 8 Jan 1993 20:59:29 GMT

In article <steph.726521280@pegasus.cs.uiuc.edu> steph@pegasus.cs.uiuc.edu (Dale Stephenson) writes:
>In <1993Jan8.032738.23621@athena.mit.edu> cmk@athena.mit.edu (Charles M Kozierok) writes:
>>based on your comments, and the post by Clay where he explains
>>what the DA and RF are (thanks, btw), i would have to conclude that
>>these statistics definitely are bogus. i don't know why anyone would
>>use them to judge much of anything. i know i wouldn't.
>
>Why use it?  Because, (lousy as it is) it's the best I have available to me.

(oh boy, i can just *see* Roger Maynard drooling over this one... :^)

all i will say is that a lousy statistic is *worse* than no statistic at all.
i believe that should be self-evident.

i understand your predicament, but i personally would rather have no answer
than the wrong one. and we have already seen at least one example where
a player has been misjudged due to this stupidistic (tm).

>It's really kind of frustrating, because it less useful than having batting
>average without OBA or SLG.  There are no end of things that can wrong with
>range factor -- balls not being distributed evenly is only one. Another is
>overall team defense -- even the worst defense still makes at least 24 outs per
>9 inning game, and they've got to go somewhere.  A team with nine atrocious
>fielders and a pitcher with 0 strikeouts would have about the same range
>factors as a team with 9 incredible fielders.

you score points in my book for admitting as much. seriously.

>So why use it all?  My alternatives would be 1) Error Totals, which is worse
>than range, and 2) Gold glove voting. Given who does the voting, I find it
>hard to believe that it correlates better with reality than range factors.
>In individual cases (Alomar?) it might, but as a general rule?

you sound like a smart guy. invent something better! start with one
of the stupidistics and make the necessary adjustments. or start with
a clean slate.

>And defense *is* important, and should be talked about.  So I can't leave it
>alone.

then i think we should at least attach a good-sized list of caveats to
any evaluation that uses those stats.

>Range does have the advantage of measuring something positive the
>player did do -- make outs.  If Alomar gets less groundballs than any other
>AL second baseman, despite making *every play* hit his way, is his stellar
>defense really that valuable to the Jays?

that is actually an interesting point.

>Shouldn't they try to put him in
>a package for Frank Thomas and sign Jeff Treadway to play second? Now, these
>doesn't help a great deal when comparing players.  But both Sandberg and
>Alomar are considered fine defensive second baseman.  But Sandberg helped his
>team more defensively, as far as I can tell.

depends on the purpose of the comparison. some people misinterpret what the
statistic means, and don't realize that Alomar would help his team a lot
more than Sandberg does if Alomar was a Cub (shudder...)

saying Alomar is less valuable to his team is fine, as long as that
isn't projected onto Alomar himself. which has been done. that is my
objection.

>>maybe subjective judgment actually wins out here. or maybe someone
>>can come up with a new stat that actually makes some sense.
>
>Defensive Average makes sense to me.  It's going in the next revision of my
>baseball game.

what about park effects? how can it be of any value without park effects?
surely you could do better than the current definition.

>>anyone who disagrees, please explain why they do make sense. because
>>it is clear that they ignore so many different important factors
>>that they are essentially useless. or maybe worse, if they fool people
>>into believing they are useful when they are not.
>
>You could say the same thing about RBI totals, and you'd be right :->.

and those have been slashed and burned on this newsgroup, n'est-ce pas?

>But I believe that *if we had no better statistic available* RBI totals *would*
>be more accurate than a random distribution in assessing worth, and most
>likely would be more valuable than the Mediots assessment.  IMHO, of course.

but that is why we use more intelligent stats like SLG.

>Note that Defensive Average does not suffer from the distribution problem,
>and therefore is much more reliable than range factor.  It still may suffer
>from park effects, and of course distribution of "hard" chances, but I'm
>inclined to believe those effects would be minor.

really? how can playing on turf versus playing in the "heavy rough" in Detroit
not have a significant effect on ground balls? i find that *very* hard to
believe.

>I definitely have more faith in it than in subjective judgement.

well i understand not wanting to use a subjective judgment. but DA sounds
pretty bad, even if better than RF. your decision to use DA instead of
subjective judgment sounds primarily like a... well... subjective judgment.

--
charles
Newsgroups: rec.sport.baseball