Of course you're right.  What I meant to say, was, what's the role of DIPS?
It's a starting place.  But you don't get the complete picture until you look at
$H, and look at it as meaningful.  

Right.  DIPS separates the part we're fairly certain about from a part that we
have difficulty measuring.  But what the hell is wrong about a best guess of
something we can't know for certain?  Especially if it can add or subtract 0.25
or 0.40 or whatever to an ERA?

Ahh, Voros  .  . I just proved that they do, to a rigor 34,202 times as great as
I would need to get it published in a scientific journal. When a pitcher changes
teams, his new $H depends on his old $H.  Period.  End of story.  No possibility
of other explanation.  It's as cut and dried as possible.

It has *never* followed that because $H correlates poorly, differences between
it must be small.

Think about this: looking at 443 pitchers who changed teams, I was able to
determine, with 95% certainty, that their old $H accounts for between 5.7 and
12.4 % of their new $H (with 9.2% likeliest).  Could I have found such a small
effect if the differences between pitchers were very small?  Unlikely.

 DIPS would be a solid concept (in fact I

DIPS is a great concept.  The notion of making a separation between that which
we're sure about and that which is vague is wonderful.   But vagueness does not
and never has and never will equal smallness.  We've only got a rough idea of
the size of the Andromeda Galaxy.

--
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Eric M. Van
em...@post.harvard.edu

". . . from that day forward she lived happily ever after.  Except for the dying
at the end.  And the heartbreak in between." - Lucius Shepard.