基礎知識

守備から独立した投手評価(DIPS)

概要

守備の影響から独立した投手の成績、あるいはその考え方や算出方法をDIPS(Defense Independent Pitching Stats)と呼ぶ。分析家のボロス・マクラッケンが「グラウンド上に飛んだ打球がアウトになるかどうかは投手ごとに安定しておらず運の影響が大きい」という発見に基づいて提唱した。基本的には、守備の関与する被安打を平準化する形で投手の成績を補正して算出する。DIPSにはその考え方に基づいた派生的な計算式が数多く存在し、一般によく利用されるのはトム・タンゴによるFIPやグラハム・マクリーによるtERA(tRA)である。

背景

ボロス・マクラッケンは、奪三振・四球・被本塁打に関しては同じ投手であれば年をまたいでも一貫した傾向があるのに対して、本塁打を除く被安打に関しては極めてばらつきが大きいことを発見した。この発見に基づき、本塁打以外の被安打の多さは運であるとして無視し、奪三振・四球・被本塁打のみによって投手を評価するDIPSを提唱した。

投手にとって被安打の多さがただの運であるとするボロス・マクラッケンの主張は、ヒットを打たれるのは投手の責任であり力のある投手は本塁打以外のヒットも打たれにくいという従来の感覚・常識に反していたため激しく批判された。しかし現在では原則として正しい理論であるとして受け入れられている。

ボロス・マクラッケンの理論に対してはいくつかの指摘もある。例えばトム・ティペットはマクラッケンの主張を批判的に検討した結果、ナックルボーラーなど一部の投手のついてはBABIP(本塁打以外の打球が安打になった割合)が低い傾向にあることを指摘した。トム・タンゴらは各種の要因がBABIPに与える相対的な影響の度合いを計測した結果「運44%・投手28%・守備17%・球場:11%」の割合で影響があるという結論を得ている。従って現在のセイバーメトリクスは投手にとってのBABIPが「完全に」運や守備によって決定されるものであるとは考えていない。

いずれにせよ重要なことは、投手は従来考えられていたほどBABIPを支配できるわけではなく、むしろ投手以外の要因が大きいこと、そしてそのことを踏まえなければ適切な投手の評価や未来の予測は行えないということである。この意味でDIPSの理論はセイバーメトリクスにおいて極めて重要なものである

関連リンク

Introduction 05. 「投手の評価(Fielding Independent Pitching)」

指標一覧

指標右側のタグは"Leaders" 内のテーブルにリンクされています。Batting > Standard と表示されていた場合、"Leaders"メニュー内の"Batting""Standard" のテーブルにリンクされています。
1B
One-base Hit
Batting > Standard
2B
Two-base Hit
Batting > Standard
3B
Three-base Hit
Batting > Standard
AVG
Batting Average
Batting > Standard
AVG
Batting Average
Batting > Advanced
AVG
hits allowed average
Pitching > Advanced
BABIP
Batting Average on Balls In Play
Batting > Advanced
BB
Base on Ball
Batting > Standard
BB
walks and given
Pitching > Standard
BB/K
walk-to-strikeout ratio
Batting > Advanced
BUH%
bunt hit percentage
Batting > Batted Ball
CG
complete game
Pitching > Standard
CS
Caught Stealing
Batting > Standard
CS
caught stealing
Pitching > Standard
CS
Caught Stealing
Fielding > Standard
CS%
Caught Stealing percentage
Fielding > Standard
CStr%
Called + swinging strike percentage
Batting > Plate Discipline
DP
Double Plays
Fielding > Standard
DPF
Double Plays Finished
Fielding > Standard
DPS
Double Plays Started
Fielding > Standard
DPT
Double Plays Turned
Fielding > Standard
ERA
earned run average
Pitching > Standard
exLI
Average Leverage Index when exiting the game
Pitching > Win Probability
FB%
fly ball percentage
Batting > Batted Ball
FB%
fly ball percentage
Pitching > Batted Ball
FP%
Fielding percentage
Fielding > Standard
FT%
Two Seam Fastball percentage
Batting > Pitch Type
FT%
Two Seam Fastball percentage
Pitching > Pitch Type
FTv
Two Seam Fastball velocity
Batting > Pitch Type
FTv
Two Seam Fastball velocity
Pitching > Pitch Type
GB%
ground ball percentage
Batting > Batted Ball
GB%
ground ball percentage
Pitching > Batted Ball
GB/FB
ground ball to fly ball ratio
Batting > Batted Ball
GB/FB
ground ball to fly ball ratio
Pitching > Batted Ball
GBOut%
ground ball out percentage
Batting > Batted Ball
GDP
Grounded into Double Play
Batting > Standard
gmLI
Average Leverage Index when entering the game
Pitching > Win Probability
HBP
Hit By Pitch
Batting > Standard
HBP
hit by pitch
Pitching > Standard
HR
home runs allowed
Pitching > Standard
IBB
Intentional Base on Ball
Batting > Standard
IBB
intentional base on balls
Pitching > Standard
IFFB%
infield fly ball percentage
Batting > Batted Ball
IFFB%
infield fly ball percentage
Pitching > Batted Ball
IFH%
infield hit percentage
Batting > Batted Ball
inLI
Average Leverage Index at the start of the inning
Pitching > Win Probability
IP
innings pitched
Pitching > Standard
K%
strikeouts rate
Batting > Advanced
K-BB%
strikeout-walk rate differential
Pitching > Advanced
LD%
line drive percentage
Batting > Batted Ball
LD%
line drive percentage
Pitching > Batted Ball
OBP
On-Base Percentage
Batting > Advanced
O-Contact%,Z-Contact%,Contact%
contact percentage
Batting > Plate Discipline
O-Contact%,Z-Contact%,Contact%
contact percentage
Pitching > Plate Discipline
OFOut%
outfield fly out percentage
Batting > Batted Ball
OPS
On-base Plus Slugging percentage
Batting > Advanced
O-Swing%,Z-Swing%,Swing%,SwStr%
swing percentage
Batting > Plate Discipline
O-Swing%,Z-Swing%,Swing%,SwStr%
swing percentage
Pitching > Plate Discipline
PA
Plate Appearance
Batting > Standard
PB
Passed Balls
Fielding > Standard
PH
Pinch Hit Opportunities
Batting > Win Probability
PhLI
Average Leverage Index while Pinch Hitting
Batting > Win Probability
pLI
Player Average Leverage Index
Batting > Win Probability
pLI
Player Average Leverage Index
Pitching > Win Probability
Pull%,Cent%,Oppo%
batted ball direction
Batting > Batted Ball
Pull%,Cent%,Oppo%
batted ball direction
Pitching > Batted Ball
R
runs allowed
Pitching > Standard
RBI
Runs Batted In
Batting > Standard
RE24
Run Above Average based on the 24 Base/Out States
Batting > Win Probability
RE24
Run Above Average based on the 24 Base/Out States
Pitching > Win Probability
REW
Wins Above Average based on the 24 Base/Out States
Batting > Win Probability
REW
Wins Above Average based on the 24 Base/Out States
Pitching > Win Probability
rPB
Passed Balls Saved runs above average
Fielding > Advanced
rSB
Stolen Base Runs Saved runs above average
Fielding > Advanced
SB
Steal a Base
Batting > Standard
SB
steal a base
Pitching > Standard
SB
Stolen Bases
Fielding > Standard
Scp%
First Baseman Scoops percentage
Fielding > Standard
SF
Sacrifice Fly
Batting > Standard
SH
Sacrifice Hit
Batting > Standard
SLG
Slugging percentage
Batting > Advanced
SO
Strike Out
Batting > Standard
Soft%,Mid%,Hard%
quality of contact stats
Batting > Batted Ball
Soft%,Mid%,Hard%
quality of contact stats
Pitching > Batted Ball
TBF
total batters faced
Pitching > Standard
TE
Throwing Errors
Fielding > Standard
WAR
wins above replacement
Batting > Value
WAR
WAR
wins above replacement
Pitching > Value
WAR
wCB/C
Curveball runs above average per 100 pitches
Batting > Pitch Value
wCB/C
Curveball runs above average per 100 pitches
Pitching > Pitch Value
wCH/C
Changeup runs above average per 100 pitches
Pitching > Pitch Value
wCT/C
Cutter runs above average per 100 pitches
Pitching > Pitch Value
wFA/C
Fastball runs above average per 100 pitches
Batting > Pitch Value
wFA/C
Fastball runs above average per 100 pitches
Pitching > Pitch Value
wFT
Two Seam Fastball runs above average
Batting > Pitch Value
wFT
Two Seam Fastball runs above average
Pitching > Pitch Value
wFT/C
Two Seam Fastball runs above average per 100 pitches
Batting > Pitch Value
wFT/C
Two Seam Fastball runs above average per 100 pitches
Pitching > Pitch Value
WP
wild pitch
Pitching > Standard
WP
Wild Pitches
Fielding > Standard
wSB
weighted Stolen Base runs
Batting > Advanced
wSF/C
Splitter runs above average per 100 pitches
Batting > Pitch Value
wSF/C
Splitter runs above average per 100 pitches
Pitching > Pitch Value
wSI/C
Sinker runs above average per 100 pitches
Batting > Pitch Value
wSI/C
Sinker runs above average per 100 pitches
Pitching > Pitch Value
wSL/C
Slider runs above average per 100 pitches
Batting > Pitch Value
wSL/C
Slider runs above average per 100 pitches
Pitching > Pitch Value
wSP/C
Special runs above average per 100 pitches
Batting > Pitch Value
wSP/C
Special runs above average per 100 pitches
Pitching > Pitch Value
Zone%,F-Strike%
pitches in the strike zone percentage
Batting > Plate Discipline
Zone%,F-Strike%
pitches in the strike zone percentage
Pitching > Plate Discipline
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