From: genetic+@pitt.edu (Dr. Dave)
Newsgroups: rec.sport.baseball
Subject: Re: Mattingly discussion, take 2.
Date: 18 Dec 92 22:09:44 GMT
Organization: Department of Industrial Engineering

Thus spake jmann@vineland.pubs.stratus.com:
>In article <949@blue.cis.pitt.edu> genetic+@pitt.edu (Dr. Dave)  
>writes:
>> Don't bother.  The same people who use real live defensive stats to  
>> rate players also tend to think that batting average with RISP is not  
>> any more useful that hat size and birthday in evaluating players, since  
>> it's just noise in the overall batting levels.  (Of course, most of us  
>> also find *any* batting average to be mostly irrelevant; OBP and SLG tell
>you more.)

>Why say "don't bother" before looking at the evidence?  

I wouldn't.

I didn't.

I *have* looked at the evidence.  Carefully.  In excruciating detail, in
fact.  And all of that evidence points to a conclusion that the pattern of
RISP batting averages seen in the major leagues is exactly what we would
expect it to be were it just a random subsample of overall batting stats,
which were themselves indpendent Bernoulli trials.

What's more, the studies I'm talking about have been reported on this net
fairly recently, by David Grabiner and others.  Now, Mr. Mattingly's Fan
may not have been around last year to see them, Jim, but I'm sure you were.

>I agree
>with you that all the stats I've seen to date show that
>BA with RISP is basically noise, fluctuating from season to season,
>with a small number of chances in the first place, and therefore
>not reliable.  But I still think that SOME players might bat
>better in some situations in other.  What if someone comes back
>with statistics that say that Joe X (or Don M) hit significantly
>better with runners in scoring position over a large number of
>at-bats. For example, if a player, over a 12 year career, hits
>50 points higher with RISP, that probably says that player does
>respond well in such situations. (Now, I haven't seen any
>stats that show anyone doing this over that period of time,

Eddie Murray might have, though I doubt it.  But this begs the question,
because even in a random population *somebody* is going to have gaudy
numbers like that, just by accident.  (Here's where the folks with no real
grasp of probability start to go into anger/denial mode.)  If you look at
enough different random sequences, eventually you'll see one that doesn't
*look* random.  It's the old "monkeys and Shakespeare" thing: generate enough
random sequences, and eventually one of them will spell out "Paul is dead;
Lundy 'til you drop" in Morse code.  

>but if someone showed them to me I'd guess they'd be significant.)

It depends on how many there are, and how long they last, and how many
different players you had to search through to find them.  

The real killer about this hypothesis is that there isn't any positive
correlation from one season to the next in who hits better than expected
in RISP situations and who doesn't.  If there were really an *ability* out
there that some people have and some don't, you'd expect the "haves" to show
up *mostly* above average all the time, and the "nots" to show either no
pattern or consistently worse than expected.  But this just doesn't happen.
Even Eddie Murray has had some stinky RISP years (independent of how good
his overall stats were), and the league's overall serial correlation from
year to year is slightly *negative*.

So, while it's not inconceivable that there might be players like this out
there, there is no evidence to back up the speculation, and there's a real
strong prima facie case that the assertion is just arrant nonsense.  Of course,
as Roger Maynard would be quick to point out, this is not a *proof* that
clutch hitters exist.  It's just a *very* good reason not to bet on them.


-- 
       David Tate        |"Out of the dugout endlessly swinging,
 dtate@unix.cis.pitt.edu | Out of the manager's throat, the sound fundamentals,
 Prof. of Story Problems | Out of the six-month season..."            
 Member ORSA, TIMS, SABR | 	Walt "Lefty" Whitman
Newsgroups: rec.sport.baseball