Part I

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=== Hiro Nakamura Dept. ===

Picking up our timeline at a tangent now -- LL time-warps us back to a friendly CERA exchange between Keith Woolner and Bill James which, echoes James' earlier refutation of Baseball Prospectus' PAP. 

James wouldn't put it that way.  I would, though.

In that earlier debate, James refuted PAP by demonstrating that pitchers with the highest PAP turned out to be more reliable than average ...

BP then smilingly patted James on the head for still being able to contribute in minor ways, at his age.  They went on publishing PAP as definitive for a few years, but since James' article, PAP quietly died as the definitive, dogmatic yardstick by which to measure MLB managerial incompetence.

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Woolner had, earlier provided a thorough and intelligent 'proof' that CERA does not exist ... the basis of his proof being that CERA was not showing up in his measurements.

In this article, Woolner relays that James calmly (and, as is typical for him, very politely) refuted the logic.  He did it this way:

(1) James set up a computer simulation in which one catcher (call him Bob Johnson) was programmed to actually have a much better CERA than another catcher (call him Koji Jerjima).

(2) James showed that Woolner's measurements of CERA indicated these two catchers to have exactly the same catching ability.

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Dr. D can well imagine Woolner's shock at this realization :- ) and his wonder at James' brilliant, elegant approach.   But Woolner rallied gamely, and strongly asserted that all this proved was that CERA probably really doesn't exist.

Um, say what?

Thusly, per Baseball Prospectus: 

(1) "There's not much practical difference between (a) a lack of ability and (b) an ability we can't measure."  (sic - Dr. D)

And therefore: 

(2) since 0.00 CERA measurements are consistent with both situations (a) catchers don't affect the pitchers at all, and (b) catchers affect pitchers a lot...

We get to place the burden of proof on the other guys, and the math shows that probably catchers don't affect the pitchers at all.

I'll let you judge that for yourself.  :- )

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=== 1,000 Light Bulbs Paradigm ===

From Jan 1., 1981 to November 10, 2009, and on every day in between, Bill James has been clear about the fact that sabermetricians are wearing red glasses, and tools scouts are wearing blue glasses.

BP, for better or worse, has the attitude "if I can't see it through my red glasses, it doesn't exist.  Unless you can show it to me.  Through red glasses."

James, and I, have the attitude "if the red glasses don't tell us anything, let's hear what the guys in the blue glasses have to say.  Especially if they all agree.  Those guys with blue glasses can be very, very good at what they do."

When all the scouts agree on something, and I can't prove them right or wrong with math?  ... my assumption is not that they're wrong, and neither is it that the scouts are irrelevant.  When all the scouts agree on something, and I don't have math to bear on the question, my assumption is that they're right.    

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BP's worldview (often) reduces the blue glasses to the point of irrelevancy:  if we can't see something with the red glasses, then we have to assume nobody sees anything!

I don't believe that.  I believe that tools scouts have light bulbs on that we don't, and a lot of them.

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James' paradigm is highly useful here.   He views sabermetricians as being in helicopters, flying over the forest.  He views tools scouts and players as being park rangers, on foot, in the forest.

Obviously the guys in the helicopters and the guys on foot are going to see different things.   Who sees the moss on the trees?  Who sees the invading hordes from the North?

We sabermetricians need to understand that although we can't see the moss, it's still there.   When 672 park rangers are telling us that the ground is damp under their feet and the vines are dripping water on them, it does us no good to tell them that they must be mistaken because it hasn't rained in 200 days.

There is no such thing as a ballplayer who disbelieves CERA -- who doesn't believe that one catcher can fool him and another cannot.  We ought to think about that.

Don Wakamatsu doesn't believe that Kenji Johjima's +2.00 CERA's were fair; he believes that his negative effect was exaggerated and overblown.

I believe the same.  I'd guess it at what, 0.50, 0.75.   Send Rob Johnson to Japan and his pitchers will probably get hit, too.

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Part III