Adjusted Range Factor (Or Why Darin Erstad Deserves Serious Consideration as AL MVP)
David Vaillette proposes a *new* defensive stat.
Adjusted Range Factor (Or Why Darin Erstad Deserves Serious Consideration
as AL MVP)
I was reading something in Rob Neyer the other day about the fact that there
is proof that good defense keeps balls that are in play (Base Hits that are
not home runs and outs that are not strike outs) from being hits and not pitching.?
That is, there is proof that it is not a skill that appears constant from
year to year for pitchers.? (The exception is apparently knuckleballers.)?
I have also read that a good stat for total team defense is outs/balls in
Outs = IP*3-K
Balls in Play = H-HR+IP*3-K
Team Defensive Rating = (IP*3-K)/(H-HR+IP-K)
It also appears to me that Zone Rating is the single most useless stat ever
computed for baseball.
What I think is a good stat is Range Factor, but it?s kind of the Avg. of
Fielding; the most useful single stat (OPS is a composite stat, and RC is
a even more a composite stat) but still potentially misleading.? For instance
do Darin Erstad?s and Wendell Magee?s current (7/15/2001) RFs of 3.71 and
3.36 mean they are both great Center Fielders?? My answer, Erstad yes, Magee
no, read on.
(Note the following are from team stats I compiled on or about July 6th.)
How are RFs different from team to team?? What will the RFs of the Diamondbacks
look like who have to perform behind Randy Johnson and Curt Shilling?? Obviously
they won?t look as good.? What about Outfielders and Infielders who play behind
Derek Lowe?? The infielders will have their stats padded, and the outfielders
stats will look worse.? And what if you are a player on the Atlanta braves
with the best defense in the league.? On the season they make 12 outs for
every 15 balls in play, while an average team makes 12 outs for every 16 balls
in play.? The have essentially robbed themselves of 1 chance to make a play
due to their efficiency.
The answer is, obviously to adjust.
The first adjustment is to compute a team?s Defensive Efficiency to the league
average.? For instance Atlanta?s DE .807 and the league average was .769,
so each member of Atlanta has their RF multiplied by .807/.769. (=1.049)?
Detroit has each member of their team multiply their RF by .736/.769 (=.959)
The 2nd Adjustment is to compute the average in-play outs per
inning for each team, or take out the strikeouts.? For instance Detroit, whose
pitchers don?t strike anybody out, has 2.416 outs per inning pitched and Arizona,
who leads the league in Ks has an average of 2.079 outs per inning pitched.?
The league average is 2.250, so for Detroit the adjustment would be 2.250/2.416
(=.93) and for Arizona, the adjustment would be 2.250 / 2.079 (=1.082).
The 3rd and final adjustment I make is an estimation of ground
balls to fly balls.? The estimation I use is a little bit lazy.? One could
and should figure out the amount of PO by outfielders, but instead I figure
out a ratio of Assists/Outs in play.? The team with the most Assists/Outs
in play is the Montreal Expos with a ratio of .570.? The Team with the least
is the Minnesota Twins with a Ratio of .459.? The league average is .512.?
Now it may be that the reason more outs are recorded by Minnesota outfielders
than any other team could be that they have fly ball pitchers on their team,
or the reason could be that they have good outfielders and bad infielders.?
I take a mid point between these two views and compute an outfield RF adjustment
of (.459/.512+1)/2 (=.948) for the Twins Outfielders and (.512/.459+1)/2 (=1.0578)
for the infielders.
My Adjusted RF subtotal is RF*Adj1*Adj2*Adj3.? Then I subtract a player?s
error rate per 9 innings for my final ?Adjusted RF?.? In my numbers there
are a couple of other things I haven?t told you about above.? I have subtracted
out Catcher Defensive numbers (Mostly just Caught Stealing) there are some
other adjustments that could be made, and others that could be made better
(Should there be a park adjustment?? A Left Right Adjustment?? Should there
be an estimation of infield flies (Team Assists ? Outfield Assists- Catcher
Assists ? IB PO)? This is what I am currently going with. ?And, as, from what
I read, Bill James would expect, and you might not, the results are not what
you would expect.
The 2002 All Defensive team so far:
C? Einar Diaz
1B Mike Sweeney
2B Adam Kennedy
SS Mike Bordick
3B Robin Ventura
???? Corey Koskie (due to the imperfections I mention Above, I have to consider
this a tie)
LF Jacque Jones
CF Darin Erstad
RF Matt Lawton
C? Damian Miller
1B Eric Karos
2B Jeff Kent
3B Craig Counsell
SS Jose Hernandez
LF Eric Owens (!?!?)
CF Jim Edmonds
???? Juan Encarnacion (tie)
RF Richard Hidalgo
AL Defensive MVP ? Darin Erstad or Mike Borkick
NL Defensive MVP ? Craig Counsell or Jose Hernandez.
Note1: For 1B I use A + DP/2 for a Range Factor Rating.? For Catchers I use
a different rating all together.
Note 2:? One problem with this system is its inability to rate an outfielder?s
arm.? For instance Outfield assists are usually considered a good rating of
an outfielder?s arm, but it is really a rating of an outfielder?s reputation.?
Nobody runs on Mondesi anymore, so he doesn?t get assists anymore.? Ivan Rodriguez
is among the last in the league in Catcher Assists because people have learned
not to run on him either.
So, using this tool, Darin Erstad has an adjusted RF of 3.56.? The team he
plays on seems to have some fly ball pitchers (or is it just because he is
so good?) but they are the 3rd best defensive team in the league.?
Mean while Magee plays for the worst defensive team in the league, and the
worst strikeout team in the league.? He is having his RF padded, and his adjusted
RF is 2.88.? This is still well above the league average of 2.65, but it is
not insanely high like Erstad?s is.? In my estimation he takes 1.16 hits per
game away from the other team per game.? If you are watching him every day,
he will get to a ball that the average centerfielder will not get to once
a game, and that no other major league center fielder will get to every other
game.? He has probably saved his pitching staff 46 runs during the year.?
Offensively he is only above average, but defensively he is in a class by
himself by him self.? Alex Rodriguez has been good, but he is only a slightly
above average SS (4.40 vs. league avg of 4.35).? Mike Sweeney has been incredible
Offensively and Defensively, but Erstad is playing for a contender, and Sweeney
Last note How the hell does a 37-year-old (Mike Bordick) play such good defense
Posted: September 03, 2002 at 06:00 AM | 13 comment(s)
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