From: cmk@athena.mit.edu (Charles M Kozierok)
Subject: Re: defensive measures of performance (was -- Re: Lists: The Best Players In Baseeball)
Keywords: RF, DA, ???
Organization: Massachusetts Institute of Technology
Distribution: na
Date: Sat, 9 Jan 1993 04:59:25 GMT

In article <steph.726550888@pegasus.cs.uiuc.edu> steph@pegasus.cs.uiuc.edu (Dale Stephenson) writes:
>In <1993Jan8.205929.9120@athena.mit.edu> cmk@athena.mit.edu (Charles M Kozierok) writes:
>
>>all i will say is that a lousy statistic is *worse* than no statistic at all.
>>i believe that should be self-evident.
>
>It depends *how* lousy the statistic.  If it says nothing more than blind picks
>would, it is a bad statistic.  If it actually runs counter to reality, it is
>evil.  If it is positive, it has some value.  Kind of like this:
>
>(If player value could be accurately measured)
>
>            Reality     Good       Bad       Lousy, but useful     Evil
>A             1          1.2        2             1.75              4
>B             2          1.9        2             1.83              3
>C             3          3.0        2             2.75              2
>D             4          3.3        2             2.58              1

that's cute. i like that. quite helpful.

btw, when i see people saying things like "Sandberg deserves to
be on the 'best of' list more than Alomar because his RF is better",
i wonder if it doesn't belong somewhere between those two right-most columns.
because a best-of list is no different than voting for the HOF.

>>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).
>
>Well, he would be misjudged if we used to proclaim Alomar worse than Steve
>Sax.  But we were comparing Alomar to Sandberg, both of home have "gold
>glove" reputations.  That Sandberg makes a lot more plays is in his favor.
>It's certainly not a clinching argument -- there are too many unknown
>variables.  But it is a pro-Sandberg data point.

if it were DA, fine. but RF depends on too many irrelevant things,
from what i have been told, like the pitching staff.

>>>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.
>
>I think so, although it doesn't solve the Sandberg vs. Alomar defensive
>issue.  I wonder if a factor like this should be considered in the MVP
>debate?  :->

i don't know. the MVP voting seems to be based on so many bogus things
that i don't think this issue would even crack the top-ten list of
"things that need to be done to make the MVP more fair".

>>>>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?
>
>Well, yes.  But my problem with RBI totals aren't that they are *evil* (see
>definition above), but that there are better tools available.  Why use RBI
>totals when OBP and SLG are in every McWeekly?

i can't stand it anymore...
why exactly does everyone call it "Mc" Weekly?
does McDonald's own it or something?

>>>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.
>
>See above.  If there is a significant park effect, it should be measurable.
>Now, I can envision problems with DA - I don't know how well they've been
>answered.  If infielders really are only measured on ground balls, we're
>missing how well they snag liners, go back for short flies, or turn double
>plays.  First basemen's ability to make catches isn't measured.  Boundaries
>cause me concerns -- what about a player making plays in someone else's
>zone.  Those could be either 1) depriving the home zone player of a chance
>he ordinarily would have made, or 2)  saving the home zone player from a
>chance he would have missed.  An imbalance between #1 and #2 would skew
>the results.  I don't have great answers myself -- but the concept of DA is
>good, and gives a stastic whole worlds better than what we had to work
>with.

i have conceded the point about park effects in DA in another post.

>>>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.
>
>True.  That's the real purpose of subjective judgement -- to find something
>better :->.

fair enough.

--
charles
Newsgroups: rec.sport.baseball