From: marc@yogi.austin.ibm.com (Marc J. Stephenson)
Newsgroups: rec.sport.baseball
Subject: Re: Net Runs Created - a new idea(?) - LONG
Date: 25 Sep 92 22:13:31 GMT
Organization: IBM, Austin

In article <6244@blue.cis.pitt.edu.UUCP> genetic+@pitt.edu (Dr. Dave) writes:
>Thus spake marc@yogi.austin.ibm.com (Marc J. Stephenson):
>>
>>I like this idea because it's basically simple, but not all outs are equal in
>>terms of runs.  The severity of an out depends upon the base situation and the
>>out situation.  An out occurring with 2 outs and nobody on is less expensive
>>in terms of expected runs than if the bases were loaded.  
>
>True.  However, there are two things to bear in mind here:
>
>	1. The batter is not responsible for the situation he faces
>	   when he comes to the plate.

No, but it sure matters to the team how he deals with it.
>
>	2. The evidence we have strongly indicates that there is no 
>	   correlation at the individual level between the type of
>	   situations the batter faces and what he does with the ball.
>	   (There are league-wide effects, like the way everybody hits
>	   better with men on base, but these seem to reflect changes
>	   in the quality of pitching, not in hitting.  David Grabiner
>	   can give you more statistical details of these arguments
>	   than you care to hear.)

Well, as anything, it all depends on what you're trying to measure.  If you're
just trying to measure how well a particular batter hits (which is certainly
reasonable), then the situation might as well be left out.  If what you're
trying to measure is overall offensive value to the team, then maybe it does
matter.  What the professor I worked with (Carl Morris, who is in SABR and
seems to have moved to Harvard, maybe) felt, and what makes sense in the
proper context, is that all that eventually matters in baseball are runs.
How effective an offensive maneuver (including stolen bases and sacrifices)
is depends on the how that maneuver translates in terms of run production.
If it improves the teams chances of scoring a run (including the 100% chance
in the case of a materialized run), then clearly that was good; otherwise, it
wasn't.  (This system doesn't really take into a account trying to improve
the teams chances of scoring a single run - obviously, the likelihood of
scoring a single run is more important than the likelihood of scoring 
several runs in the potentially deciding bottom-half of an inning in a tied
game.)

>
>That being the case, it isn't clear that we *want* to credit the guy who hits
>a grand slam more than the guy who hits a solo HR, on the grounds that the
>difference between the two wasn't under the control of the batter in any way
>that matters.  Nobody can hit HR on request; the timing of them is random
>(though of course the overall *frequency* of them varies greatly from one
>batter to another).

The guy who hits the grand slam doesn't necessarily get so much more credit than
the guy with the solo.  I don't remember the numbers, but say that in the case
of no outs and the bases loaded, the expected runs are 2.5, and the expected
runs for no outs and none on is 0.5; the grand salami generated 4 runs and
left the situation with 0.5 runs expected, generating a net runs produced of
+2.0 in that event.  The solo job generated exactly +1 net run, since the
situation is still the same.  Okay, so it does look like the grand slam was
worth more for the same event, that the batter is benefitting from a random
situation; however, that same batter also is subject to higher penalties if
he doesn't come through (a triple play would cost him -2.5 net runs).  

To me, it does feel valid in that grounding into a double play with 1 out
feels a lot worse than grounding out to second to end the inning.  It's 
the same ball; the batter was subject to a random situation - is the double
play more costly?  Obviously (well, to me).  Is the grand slam more valuable 
(in terms of runs) than a solo?  Yep.  Why not show it?  But, agreed, it
doesn't necessarily show that a given batter is more skilled than another.

>
>>Using the
>>average runs/out allows the simple calculations, and maybe that's okay, but
>>it does lack the situational aspects.  Maybe it all works out over the length
>>of a season in terms of situations faced, but I wouldn't count on it.
>
>It doesn't, but see above.  Does it make Joe Carter a better hitter, to note
>that he faced much higher-leverage situations on average than did Ken Griffey?
>Or should we try to "level the field" in order to compare Griffey's ability
>(i.e. potential to help an offense) with Carter's ability?

Gee, I dunno.  My guess is that Carter probably failed enough in those
higher-leveraged situations to even things out, particularly in years past.
If Carter significantly affects his teams ability to score runs more than 
Griffey, then it seems reasonable to credit him for it.  There is certainly
an equally justifiable system of trying to remove any external situations
from a player's performance, which you seem to be in favor of (and it's
certainly simpler to do so - and even statistics might bear you out).  No
real argument there.
>
>>I used a net runs expected table when I was doing some scoring work with the
>>University of Texas baseball team in fall of '81 (Clemens,Schiraldi,Owen,
>>Brumley,Capel,Hearron).  
>
>You might want to look at what Gary Skoog did with the 1986(?) season, using
>the expected runs table and situational data from Project Scoresheet.  It's
>in one of those Bill James Abstracts from the late 80's; I can look up the
>exact year at home.
>
I was a team captain for Project Scoresheet in either it's first or second year;
I had to coordinate getting people to score games for the Houston Astros for
the entire season.  It was a mess at the time trying to get people to cover
all the games; it was a real mess for me because I'm 200 miles away from
Houston and the coverage here was awful (I had to pick up Houston AM radio a
good deal of the time, a mixed proposition at best).  One of my more prolific
scorers somehow crapped out on me and I ended up missing a lot of the games;
guess that's why I didn't get mentioned in the Abstract as a contributor.  All
I got out of it was a big phone bill.  Oh well, that's another story.
>
>
>-- 
>       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
-- 
Marc Stephenson		    IBM AWD (Advanced Workstations Division - Austin,TX)
DISCLAIMER: The content of this posting is independent of official IBM position.
INTERNET->marc@austin.ibm.com      VNET: MARC at AUSVMQ        IBM T/L: 678-3189