In
baseball
Baseball is a bat-and-ball sport played between two teams of nine players each, taking turns batting and fielding. The game occurs over the course of several plays, with each play generally beginning when a player on the fielding tea ...
, wOBA (
/'woʊbə/, or weighted on-base average) is a statistic, based on
linear weights
In statistics, linear regression is a linear approach for modelling the relationship between a scalar response and one or more explanatory variables (also known as dependent and independent variables). The case of one explanatory variable is call ...
, designed to measure a player's overall offensive contributions per plate appearance. It is formed from taking the observed run values of various offensive events, dividing by a player's plate appearances, and scaling the result to be on the same scale as
on-base percentage
In baseball statistics, on-base percentage (OBP) measures how frequently a batter reaches base. An official Major League Baseball (MLB) statistic since 1984, it is sometimes referred to as on-base average (OBA), as it is rarely presented as a ...
. Unlike statistics like
OPS
In ancient Roman religion, Ops or ''Opis'' (Latin: "Plenty") was a fertility deity and earth goddess of Sabine origin. Her equivalent in Greek mythology was Rhea.
Iconography
In Ops' statues and coins, she is figured sitting down, as Chthon ...
, wOBA attempts to assign the proper value for each type of hitting event. It was created by
Tom Tango
Tom Tango and "TangoTiger" are aliases used online by a baseball sabermetrics and ice hockey statistics analyst. He runs the ''Tango on Baseball'' sabermetrics website and is also a contributor to ESPN's baseball blog ''TMI (The Max Info)''. Tango ...
and his coauthors for ''The Book: Playing the Percentages in Baseball''.
Usage
In 2008,
sabermetrics
Sabermetrics, or originally SABRmetrics, is the empirical analysis of baseball, especially baseball statistics that measure in-game activity. Sabermetricians collect and summarize the relevant data from this in-game activity to answer specific ques ...
website
FanGraphs began listing the current and historical wOBA for all players in
Major League Baseball
Major League Baseball (MLB) is a professional baseball organization and the oldest major professional sports league in the world. MLB is composed of 30 total teams, divided equally between the National League (NL) and the American League (AL), ...
. It forms the basis of the offensive component of their
wins above replacement
Wins Above Replacement or Wins Above Replacement Player, commonly abbreviated to WAR or WARP, is a non-standardized sabermetric baseball statistic developed to sum up "a player's total contributions to his team". A player's WAR value is claimed to ...
(WAR) metric. Sites such as
The Hardball Times
The Hardball Times (abbreviated as THT) is a website which publishes news, original comments and statistical analysis of baseball each week Monday through Friday, in addition to the Hardball Times Annual book which features essays by leading sabe ...
have studied wOBA and found it to perform comparably to or better than other similar tools (
OPS
In ancient Roman religion, Ops or ''Opis'' (Latin: "Plenty") was a fertility deity and earth goddess of Sabine origin. Her equivalent in Greek mythology was Rhea.
Iconography
In Ops' statues and coins, she is figured sitting down, as Chthon ...
,
RC, etc.) used in sabermetrics to estimate runs. ''The Book'' uses wOBA in numerous studies to test the validity of many aspects of baseball conventional wisdom.
The benefit of wOBA compared to other offensive value statistics is that it values not just ''whether'' the runner reached base but ''how''. Events like home runs, walks, singles, etc. are given their own weight (or coefficient) within the linear formula. The weighting is based on the increase in expected runs for the event type as compared to an out. The coefficients change each season
based upon how often each event occurs.
Because the coefficients are derived from expected run value, we can use wOBA to estimate a few more things about a player's production and baseball as a whole. When using the formula (shown below), the numerator side on its own will give us an estimate of how many runs a player is worth to his team. Similarly, a team's wOBA is a good estimator of team runs scored, and deviations from predicted runs scored indicate a combination of situational hitting and base running.
2019 Formula
Per
Fangraphs, the formula for wOBA in the 2019 season was:
where:
* ''NIBB'' = ''
Non-intentional bases on balls
A base on balls (BB), also known as a walk, occurs in baseball when a batter receives four pitches that the umpire calls '' balls'', and is in turn awarded first base without the possibility of being called out. The base on balls is defined in Se ...
''
* ''HBP'' = ''
Hit by pitch
In baseball, hit by pitch (HBP) is an event in which a batter or his clothing or equipment (other than his bat) is struck directly by a pitch from the pitcher; the batter is called a hit batsman (HB). A hit batsman is awarded first base, provided ...
''
* ''1B'' = ''
Single
Single may refer to:
Arts, entertainment, and media
* Single (music), a song release
Songs
* "Single" (Natasha Bedingfield song), 2004
* "Single" (New Kids on the Block and Ne-Yo song), 2008
* "Single" (William Wei song), 2016
* "Single", by ...
''
* ''2B'' = ''
Double
A double is a look-alike or doppelgänger; one person or being that resembles another.
Double, The Double or Dubble may also refer to:
Film and television
* Double (filmmaking), someone who substitutes for the credited actor of a character
* Th ...
''
* ''3B'' = ''
Triple
Triple is used in several contexts to mean "threefold" or a " treble":
Sports
* Triple (baseball), a three-base hit
* A basketball three-point field goal
* A figure skating jump with three rotations
* In bowling terms, three strikes in a row
* ...
''
* ''HR'' = ''
Home run
In baseball, a home run (abbreviated HR) is scored when the ball is hit in such a way that the batter is able to circle the bases and reach home plate safely in one play without any errors being committed by the defensive team. A home run i ...
''
—————
* ''AB'' = ''
at bat
In baseball, an at bat (AB) or time at bat is a batter's turn batting against a pitcher. An at bat is different from a plate appearance. A batter is credited with a plate appearance regardless of what happens during their turn at bat, but a batt ...
''
* ''BB'' = ''
Base on balls
A base on balls (BB), also known as a walk, occurs in baseball when a batter receives four pitches that the umpire calls '' balls'', and is in turn awarded first base without the possibility of being called out. The base on balls is defined in Se ...
''
* ''IBB'' = ''
Intentional base on balls
A base on balls (BB), also known as a walk, occurs in baseball when a batter receives four pitches that the umpire calls '' balls'', and is in turn awarded first base without the possibility of being called out. The base on balls is defined in Se ...
''
* ''SF'' = ''
sacrifice flies
In baseball, a sacrifice fly (sometimes abbreviated to sac fly) is defined by Rule 9.08(d):
"Score a sacrifice fly when, before two are out, the batter hits a ball in flight handled by an outfielder or an infielder running in the outfield in fair o ...
''
* ''HBP'' = ''
Hit by pitch
In baseball, hit by pitch (HBP) is an event in which a batter or his clothing or equipment (other than his bat) is struck directly by a pitch from the pitcher; the batter is called a hit batsman (HB). A hit batsman is awarded first base, provided ...
''
2018 Formula
The formula for the 2018 season was:
* ''NIBB'' = ''
Non-intentional bases on balls
A base on balls (BB), also known as a walk, occurs in baseball when a batter receives four pitches that the umpire calls '' balls'', and is in turn awarded first base without the possibility of being called out. The base on balls is defined in Se ...
''
* ''HBP'' = ''
Hit by pitch
In baseball, hit by pitch (HBP) is an event in which a batter or his clothing or equipment (other than his bat) is struck directly by a pitch from the pitcher; the batter is called a hit batsman (HB). A hit batsman is awarded first base, provided ...
''
* ''1B'' = ''
Single
Single may refer to:
Arts, entertainment, and media
* Single (music), a song release
Songs
* "Single" (Natasha Bedingfield song), 2004
* "Single" (New Kids on the Block and Ne-Yo song), 2008
* "Single" (William Wei song), 2016
* "Single", by ...
''
* ''2B'' = ''
Double
A double is a look-alike or doppelgänger; one person or being that resembles another.
Double, The Double or Dubble may also refer to:
Film and television
* Double (filmmaking), someone who substitutes for the credited actor of a character
* Th ...
''
* ''3B'' = ''
Triple
Triple is used in several contexts to mean "threefold" or a " treble":
Sports
* Triple (baseball), a three-base hit
* A basketball three-point field goal
* A figure skating jump with three rotations
* In bowling terms, three strikes in a row
* ...
''
* ''HR'' = ''
Home run
In baseball, a home run (abbreviated HR) is scored when the ball is hit in such a way that the batter is able to circle the bases and reach home plate safely in one play without any errors being committed by the defensive team. A home run i ...
''
—————
* ''AB'' = ''
at bat
In baseball, an at bat (AB) or time at bat is a batter's turn batting against a pitcher. An at bat is different from a plate appearance. A batter is credited with a plate appearance regardless of what happens during their turn at bat, but a batt ...
''
* ''BB'' = ''
Base on balls
A base on balls (BB), also known as a walk, occurs in baseball when a batter receives four pitches that the umpire calls '' balls'', and is in turn awarded first base without the possibility of being called out. The base on balls is defined in Se ...
''
* ''IBB'' = ''
Intentional base on balls
A base on balls (BB), also known as a walk, occurs in baseball when a batter receives four pitches that the umpire calls '' balls'', and is in turn awarded first base without the possibility of being called out. The base on balls is defined in Se ...
''
* ''SF'' = ''
sacrifice flies
In baseball, a sacrifice fly (sometimes abbreviated to sac fly) is defined by Rule 9.08(d):
"Score a sacrifice fly when, before two are out, the batter hits a ball in flight handled by an outfielder or an infielder running in the outfield in fair o ...
''
* ''HBP'' = ''
Hit by pitch
In baseball, hit by pitch (HBP) is an event in which a batter or his clothing or equipment (other than his bat) is struck directly by a pitch from the pitcher; the batter is called a hit batsman (HB). A hit batsman is awarded first base, provided ...
''
Ranges for elite, very good, etc.
The following table serves as an aggregate summary of various wOBA scales available online.
Original Formula
The formula below appeared in ''The Book.''
where:
* ''NIBB'' = Non-intentional
bases on balls
A base on balls (BB), also known as a walk, occurs in baseball when a batter receives four pitches that the umpire calls '' balls'', and is in turn awarded first base without the possibility of being called out. The base on balls is defined in Se ...
* ''HBP'' =
Hit by pitch
In baseball, hit by pitch (HBP) is an event in which a batter or his clothing or equipment (other than his bat) is struck directly by a pitch from the pitcher; the batter is called a hit batsman (HB). A hit batsman is awarded first base, provided ...
* ''1B'' =
Single
Single may refer to:
Arts, entertainment, and media
* Single (music), a song release
Songs
* "Single" (Natasha Bedingfield song), 2004
* "Single" (New Kids on the Block and Ne-Yo song), 2008
* "Single" (William Wei song), 2016
* "Single", by ...
* ''RBOE'' = Reached base on
error
An error (from the Latin ''error'', meaning "wandering") is an action which is inaccurate or incorrect. In some usages, an error is synonymous with a mistake. The etymology derives from the Latin term 'errare', meaning 'to stray'.
In statistics ...
* ''2B'' =
Double
A double is a look-alike or doppelgänger; one person or being that resembles another.
Double, The Double or Dubble may also refer to:
Film and television
* Double (filmmaking), someone who substitutes for the credited actor of a character
* Th ...
* ''3B'' =
Triple
Triple is used in several contexts to mean "threefold" or a " treble":
Sports
* Triple (baseball), a three-base hit
* A basketball three-point field goal
* A figure skating jump with three rotations
* In bowling terms, three strikes in a row
* ...
* ''HR'' =
Home run
In baseball, a home run (abbreviated HR) is scored when the ball is hit in such a way that the batter is able to circle the bases and reach home plate safely in one play without any errors being committed by the defensive team. A home run i ...
* ''PA'' =
Plate appearance
In baseball statistics, a player is credited with a plate appearance (denoted by PA) each time he completes a turn batting. Under Rule 5.04(c) of the Official Baseball Rules, a player completes a turn batting when he is put out or becomes a runner ...
Citations
References
*
Tom Tango
Tom Tango and "TangoTiger" are aliases used online by a baseball sabermetrics and ice hockey statistics analyst. He runs the ''Tango on Baseball'' sabermetrics website and is also a contributor to ESPN's baseball blog ''TMI (The Max Info)''. Tango ...
, Mitchel Lichtman, and Andrew Dolphin. ''The Book: Playing the Percentages in Baseball''. Washington, D.C.: Potomac Books, 2007. .
{{Baseball statistics
Batting statistics