Editing Sabermetrics

{{short description|Analysis of baseball statistics}}
[[File:Bill James 2010.jpg|thumb|right|[[Bill James]], who coined the term "sabermetrics"]]

'''Sabermetrics''' (originally '''SABRmetrics''')  is the original or blanket term for [[sports analytics]] in the US, the [[empirical]] analysis of [[baseball]], especially the development of [[advanced metrics]] based on [[baseball statistics]] that measure in-game activity. The term is derived from the movement's progenitors, members of the [[Society for American Baseball Research]] (SABR), founded in 1971, and was coined by [[Bill James]], 
(in 1980, according to SABR.org), who is one of its pioneers and considered its most prominent advocate and public face.<ref name="Monebyall2" />

The term '''moneyball''' is used for the practice of using metrics to identify "undervalued players" and sign them to what ideally will become "below market value" contracts, which debuted in the efforts of small-market teams to compete with the much greater resources of big-market organizations.

== Early history ==
[[File:Henry Chadwick (NYPL b13537024-56451) (cropped).jpg|thumb|right|English-American sportswriter [[Henry Chadwick (writer)|Henry Chadwick]], the "father" of baseball statistics]]

English-American sportswriter [[Henry Chadwick (writer)|Henry Chadwick]] developed the [[Box score (baseball)|box score]] in New York City in 1858. This was the first way statisticians were able to describe the sport of baseball by numerically tracking various aspects of game play.<ref name=":0">{{Cite journal|last=Puerzer|first=Richard J.|date=Fall 2002|title=From Scientific Baseball to Sabermetrics: Professional Baseball as a Reflection of Engineering and Management in Society|journal=NINE: A Journal of Baseball History and Culture|volume=11|pages=34–48|doi=10.1353/nin.2002.0042|s2cid=154849268}}</ref> The creation of the box score has given baseball statisticians a summary of the individual and team performances for a given game.<ref>{{Cite web|url=http://www.baseballhalloffame.org/hofers/detail.jsp?playerId=492558|title=The Hall of Famers - Henry Chadwick|url-status=dead|archive-url=https://web.archive.org/web/20080412093802/http://www.baseballhalloffame.org/hofers/detail.jsp?playerId=492558|archive-date=2008-04-12}}</ref>

What would become the earliest Sabermetrics research in the 1970s and 1980s began in the middle of the 20th century with the writings of [[Earnshaw Cook]], one of the earliest baseball analysts. Cook's 1964 book ''Percentage Baseball'' was one of the first of its kind.<ref name="albert2">{{cite book|title=Curve Ball: Baseball, Statistics, and the Role of Chance in the Game|last=Albert|first=James|publisher=[[Springer Science+Business Media|Springer]]|year=2001|isbn=0-387-98816-5|pages=170–171|author2=Jay M. Bennett}}</ref> At first, most organized baseball teams and professionals dismissed Cook's work as meaningless. The idea of a science of baseball statistics began to achieve legitimacy in 1977 when [[Bill James]] began releasing ''Baseball Abstracts'', his annual compendium of baseball data.<ref>{{cite web|url=https://www.pbs.org/thinktank/transcript1197.html|title=Bill James, Beyond Baseball|date=June 28, 2005|publisher=[[Public Broadcasting Service|PBS]]|access-date=November 2, 2007|work=[[Think Tank with Ben Wattenberg]]}}</ref><ref>{{cite news|url=http://www.opinionjournal.com/la/?id=110010232|title=Sultan of Stats|last=Ackman|first=D.|date=May 20, 2007|newspaper=[[The Wall Street Journal]]|access-date=November 2, 2007}}</ref> However, James's ideas were slow to find widespread acceptance.<ref name="Monebyall2"/>

Bill James believed there was a widespread misunderstanding about how the game of baseball was played, claiming the sport was not defined by its rules but actually, as summarized by engineering professor Richard J. Puerzer, "defined by the conditions under which the game is played &ndash; specifically, the ballparks but also the players, the ethics, the strategies, the equipment, and the expectations of the public."<ref name=":0" /> Early Sabermetricians &ndash; sometimes considered baseball statisticians &ndash; began trying to enhance such fundamental baseball statistics as [[Batting average (baseball)|batting average]] (simply hits divided by at-bats) with advanced mathematical formulations.<ref name="jarvis">{{Cite web|url=http://knology.net/~johnfjarvis/runs_survey.html|title=A Survey of Baseball Player Performance Evaluation Measures|last=Jarvis|first=J.|date=2003-09-29|access-date=2007-11-02}}</ref><ref name=":1" /> The correlation between team batting average and runs scored was also examined,<ref name="jarvis" /> as runs &ndash; not hits &ndash; win ballgames. Thus, a good measure of a player's worth would be his ability to help his team score runs, which was observed to be highly correlated with his number of times on base &ndash; leading to the development of a new stat, "on-base percentage".

[[File:Davey Johnson 1986.jpg|thumb|right|MLB [[advanced metrics]] pioneer [[Davey Johnson]] (in 1986)]]

Before Bill James popularized sabermetrics, [[Davey Johnson]], then a second baseman playing for the early 1970s [[Baltimore Orioles]] of [[Major League Baseball]] (MLB), used an [[IBM System/360]] at team owner [[Jerold Hoffberger]]'s brewery to write a [[FORTRAN]]-based baseball [[computer simulation]]. In spite of his results, he was unable to persuade his manager [[Earl Weaver]] that he should bat second in the lineup. He wrote [[IBM BASIC]] programs to help him manage the [[Tidewater Tides]], and after becoming manager of the [[New York Mets]] in 1984, he arranged for a team employee to write a [[dBASE II]] application to compile and store [[advanced metrics]] on team statistics.<ref name="porter198405292">{{cite news|url=https://books.google.com/books?id=ZqO7wRZjZQQC&pg=PA210|title=The PC Goes to Bat|date=1984-05-29|work=[[PC Magazine]] |pages=209|access-date=24 October 2013|author=Porter, Martin}}</ref> [[Craig R. Wright]] was another employee in MLB, working with the [[Texas Rangers (baseball)|Texas Rangers]] in the early 1980s. During his time with the Rangers, he became known as the first front office employee in MLB history to work under the title "sabermetrician".<ref>[http://www.rotojunkie.com/index.php?art/id:10 RotoJunkie – Roto 101 – Sabermetric Glossary (powered by evoArticles)<!-- Bot generated title -->] {{webarchive|url=https://web.archive.org/web/20070910212350/http://www.rotojunkie.com/index.php?art%2Fid%3A10 |date=2007-09-10 }}</ref><ref>[http://www.baseballspast.com/radio.htm BaseballsPast.com<!-- Bot generated title -->]</ref>

[[David Smith (baseball historian)|David Smith]] founded [[Retrosheet]] in 1989, with the objective of computerizing the box score of every major league baseball game ever played, in order to more accurately collect and compare the statistics of the game.

[[File:Billy Beane 1989.jpg|thumb|right|[[Billy Beane]] as a player in 1989]]
The [[Oakland Athletics]] began to use a more quantitative approach to baseball by focusing on sabermetric principles in the 1990s. This initially began with [[Sandy Alderson]] as the [[General manager (baseball)|general manager]] of the team when he used the principles toward obtaining relatively undervalued players.<ref name="Monebyall2">{{cite book|last=Lewis|first=Michael M.|title=Moneyball: The Art of Winning an Unfair Game|title-link=Moneyball: The Art of Winning an Unfair Game|publisher=[[W. W. Norton]]|year=2003|isbn=0-393-05765-8|location=[[New York City|New York]]|author-link=Michael Lewis}}</ref> His ideas were continued when [[Billy Beane]] took over as general manager in 1997, a job he held until 2015, and hired his assistant [[Paul DePodesta]].<ref name=":1">{{cite news|url=http://www.sfgate.com/cgi-bin/article.cgi?file=/chronicle/archive/2003/06/01/RV145326.DTL|title=Billy Beane's brand-new ballgame|last=Kipen|first=D.|date=June 1, 2003|newspaper=[[San Francisco Chronicle]]|access-date=November 2, 2007}}</ref> During the 2002 season, a noted "moneyball" Oakland A's team went on to win 20 games in a row,<ref>{{cite web|title=Franchise Timeline|url=http://oakland.athletics.mlb.com/oak/history/timeline.jsp|archive-url=https://web.archive.org/web/20100330092153/http://oakland.athletics.mlb.com/oak/history/timeline.jsp|url-status=dead|archive-date=March 30, 2010}}</ref> a term (and approach to the game) which soon gained national recognition when [[Michael Lewis]] published ''[[Moneyball: The Art of Winning an Unfair Game]]'' (where "unfair" reflected the disparity in resources available to the big market teams versus the small) in 2003 to detail Beane's use of advanced metrics. In 2011, a film based on Lewis' book &ndash; also called ''[[Moneyball (film)|Moneyball]] &ndash;'' was released and gave broad exposure to the techniques used in the Oakland Athletics' front office.

== Traditional measurements ==
Sabermetrics reflected a desire by a handful of baseball enthusiasts to expand their understanding of the game by revealing new insights that may have been hidden in its traditional statistics. Their early efforts ultimately evolved into evaluating players in every aspect of the game, including batting, pitching, baserunning, and fielding. 

=== Batting measurements ===
[[File:Ted Williams 1940 Play Ball.jpeg|thumb|right|[[Ted Williams]], the last MLB player to bat .400 for a season (in 1941)]]

A ballplayer's [[batting average]] (BA) (simply [[Hit (baseball)|hits]] divided by [[At bat|at-bats]]) was the historic measure of a player's offensive performance, enhanced by [[slugging average|slugging percentage]] (SA){{efn|name=powerhouse|Calculated by dividing [[total bases]] (the non-situational cumulative tally of all hits) by the total number of times at bat.}} which incorporated their ability to hit for power.  

Bill James, along with other early sabermetricians, was concerned that batting average did not incorporate other ways a batter can reach base besides a hit – as a batter on base can score runs, and runs, not hits, win ballgames.<ref name=":12">{{Cite book|last=Albert|first=Jim|title=Mathematics and Sports|publisher=MAA|others=Contributor : Mathematical Association of America|year=2010|isbn=9780883853498|editor-last=Joseph A. Gallian|pages=3–14|chapter=Sabermetrics: The Past, the Present, and the Future|volume=43|chapter-url=http://www.mathaware.org/mam/2010/essays/AlbertSabermetrics.pdf|jstor=10.4169/j.ctt6wpwsw.4}}</ref> 

Even though slugging percentage and an early form of [[on-base percentage]] (OBP) &ndash; which takes into accounts [[base on ball]]s ("walks") and [[Hit by pitch|hit-by-pitch]]es &ndash; date to at least 1941,<ref>{{cite news |url=https://www.newspapers.com/clip/117560636/the-powerhouse-column/ |title=The PowerHouse (column) |first=Jimmy |last=Powers |newspaper=[[New York Daily News|Daily News]] |location=New York City |page=45 |date=June 3, 1941 |accessdate=January 30, 2023 |via=newspapers.com}}</ref> pre-dating both Bill James (born 1949) and SABR (formed 1971),<ref name=":12" /> enhanced focus was put on the relationship of times on base and run scoring by early SABR-era baseball statistical pioneers. 

SA and OBP were combined to create the modern statistic [[on-base plus slugging]] (OPS). OPS is the sum of the on-base percentage and the slugging percentage. This modern statistic has become useful in comparing players and is a powerful method of predicting runs scored by any given player.<ref name=":022">{{cite web|url=http://baseball1.com/baseball-archive/sabermetrics/sabermetric-manifesto/|title=The Sabermetric Manifesto|last=Grabiner|first=David J.|work=The Baseball Archive}}</ref>  An enhanced version of OPS, "OPS+", incorporates OPS, historic statistics, ballpark considerations, and defensive position weightings to attempt to allow player performance from different eras to be compared.

Some other advanced metrics used to evaluate batting performance are [[weighted on-base average]], [[secondary average]], [[runs created]], and [[equivalent average]].

=== Pitching measurements ===
[[File:Ed Walsh portrait 1911.jpg|thumb|right|[[Ed Walsh]], whose career 1.82 ERA is the lowest in MLB history]]
The traditional measure of pitching performance is the [[earned run average]] (ERA). It is calculated as [[earned run]]s allowed per nine innings. Earned run average does not separate the ability of the pitcher from the abilities of the fielders that he plays with.<ref name=":5">{{Cite web|url=http://www.baseballprospectus.com/article.php?articleid=878|title=Pitching and Defense: How Much Control Do Hurlers Have?|last=McCracken|first=Voros|date=January 23, 2001|website=Baseball Prospectus}}</ref> Another classic measure for pitching is a pitcher's [[winning percentage]]. Winning percentage is calculated by dividing wins by the total number of decisions (wins plus losses). Winning percentage is also heavily dependent on the pitcher's team, particularly on the number of runs it scores.

Sabermetricians have attempted to find different measures of pitching performance that exclude the performances of the fielders involved. One of the earliest developed, and one of the most popular in use, is [[walks plus hits per inning pitched]] (WHIP), which while not completely defense-independent, tends to indicate how many times a pitcher is likely to put a player on base (either via walk, hit-by-pitch, or base hit) and thus how effective batters are against a particular pitcher in reaching base.

A later development was the creation of [[defense independent pitching statistics]] (DIPS) system. [[Voros McCracken]] has been credited with the development of this system in 1999.<ref>{{Cite journal|last1=Basco|first1=Dan|last2=Davies|first2=Michael|date=Fall 2010|title=The Many Flavors of DIPS: A History and an Overview|journal=Baseball Research Journal|volume=32|issue=2}}</ref> Through his research, McCracken was able to show that there is little to no difference between pitchers in the number of hits they allow on balls put into play &ndash; regardless of their skill level.<ref name=":4">{{Cite web|url=http://www.beyondtheboxscore.com/2014/1/17/5309808/how-has-sabermetrics-changed-baseball|title=How has sabermetrics changed baseball?|last=Ball|first=Andrew|date=January 17, 2014|website=Beyond the Box Score}}</ref> Some examples of these statistics are [[Defense-Independent ERA|defense-independent ERA]], fielding independent pitching, and [[Defense-Independent Component ERA|defense-independent component ERA]]. Other sabermetricians have furthered the work in DIPS, such as [[Tom Tango]] who runs the ''Tango on Baseball'' sabermetrics website.

''[[Baseball Prospectus]]'' created another statistics called the [[peripheral ERA]]. This measure of a pitcher's performance takes hits, walks, home runs allowed, and strikeouts while adjusting for ballpark factors.<ref name=":5" /> Each ballpark has different dimensions when it comes to the outfield wall so a pitcher should not be measured the same for each of these parks.<ref name=":62">{{Cite book|title=The Sabermetric Revolution: Assessing the Growth of Analytics in Baseball|last1=Baumer|first1=Benjamin|last2=Zimbalist|first2=Andrew|publisher=University of Pennsylvania Press|year=2014|author-link=Ben Baumer}}</ref>

[[Batting average on balls in play]] (BABIP) is another useful measurement for determining pitchers' performance.<ref name=":4" /> When a pitcher has a high BABIP, they will often show improvements in the following season, while a pitcher with low BABIP will often show a decline in the following season.<ref name=":4" /> This is based on the statistical concept of [[regression to the mean]]. Others have created various means of attempting to [[Pitch quantification|quantify individual pitches]] based on characteristics of the pitch, as opposed to runs earned or balls hit.

== Advanced methods ==
[[Value over replacement player]] (VORP) {{clarification needed span|text=was once considered a popular sabermetric statistic.|reason=What became of it, and why - with appropriate citation(s), please.|date=July 2024}} This statistic attempts to demonstrate how much a player contributes to his team in comparison to a hypothetical player performing at the minimum level needed to hold a roster position on a major league team. It was invented by Keith Woolner, a former writer for the sabermetric group/website ''Baseball Prospectus''.

[[Wins above replacement]] (WAR) is another popular sabermetric statistic for evaluating a player's contributions to his team. Similar to VORP, WAR compares a given player to a replacement-level player in order to determine the number of additional wins the player provides to his team relative to an average ballplayer at his position.<ref name=":7">{{Cite web|url=http://www.espn.com/blog/sweetspot/post/_/id/27050/what-we-talk-about-when-we-talk-about-war|title=What we talk about when we talk about WAR|last=Schoenfield|first=David|date=July 19, 2012|website=ESPN.com}}</ref> WAR, like VORP a ''cumulative'' statistic, heavily reflects the amount of a player's playing time.<ref name=":7" />

"Static" statistics based on simple ratios of already accumulated data (like batting average) and accumulative tallies (such as pitching wins) do not fully reveal all aspects of the game represented in their numeric totals.<ref name=":8">{{Cite book|last1=John T. Saccoman|title=Practicing Sabermetrics: Putting the Science of Baseball Statistics to Work|last2=Gabriel R. Costa|last3=Michael R. Huber|publisher=McFarland & Company|year=2009|isbn=978-0-7864-4177-8|location=United States of America }}</ref>{{rp|189–198}} Advanced metrics are increasingly developed and targeted to addressing ''in-game'' activities (such as when a team should attempt to [[Stolen base|steal]] a base,<ref>{{Cite news|url=http://www.fangraphs.com/blogs/the-changing-caught-stealing-calculus-2/|title=The Changing Caught-Stealing Calculus {{!}} FanGraphs Baseball|newspaper=FanGraphs Baseball|language=en-us|access-date=2016-12-06}}</ref> and when to bring [[relief pitcher|closers]] in).

== Applications ==
Sabermetrics are commonly used for everything from sportswriting to baseball Hall of Fame consideration, selecting player match-ups and evaluating in-game strategic options.  Advanced statistical measures may be utilized in determining in-season and end-of-the-season awards (such as Player of the Week and MVP).  Those which are most useful in evaluating past performance and predicting future outcomes are valuable in determining a player's contributions to his team,<ref name=":022" /> potential trades, contract negotiations, and arbitration.

Recently,{{when|date=July 2024}} sabermetrics has been expanded to examining ballplayer minor league performance in AA and AAA ball in a manner similar to evaluating it at the Major League level, known as Minor-League Equivalency.<ref name=":022" /> 

==Advancements from 1985–present ==
{{expand section|date=July 2024}}

Bill James' two books, ''[[The Bill James Historical Baseball Abstract]]'' (1985) and ''[[Win Shares]]'' (2002) have continued to advance the field of sabermetrics.<ref name="james2">{{cite web|url=http://static.espn.go.com/mlb/s/2002/1105/1456563.html|title=Red Sox hire James in advisory capacity|last=Neyer|first=Rob|date=November 5, 2002|access-date=March 7, 2009|work=[[ESPN.com]]}}</ref> The work of his former assistant [[Rob Neyer]], who later became a senior writer at ESPN.com and national baseball editor of SBNation, also contributed to popularizing sabermetrics since the mid-1980s.<ref>{{cite news|url=http://www.hardballtimes.com/main/article/rob-neyer-interview/|title=Rob Neyer Interview|last=Jaffe|first=C.|date=October 22, 2007|work=[[The Hardball Times]]|access-date=November 2, 2007}}</ref>

[[Nate Silver]], a former writer and managing partner of ''Baseball Prospectus'', invented [[PECOTA]] (''Player Empirical Comparison and Optimization Test Algorithm''<ref>{{Cite web|url=http://www.baseballprospectus.com/glossary/index.php?search=PECOTA|title=Baseball Prospectus: Glossary|website=www.baseballprospectus.com|access-date=2016-05-05}}</ref>) in 2002–2003, introducing it to the public in the book ''Baseball Prospectus'' in 2003.<ref>Nate Silver, "Introducing PECOTA," in Gary Huckabay, [[Christina Kahrl|Chris Kahrl]], Dave Pease ''et al.'', Eds., ''Baseball Prospectus 2003'' (Dulles, VA: Brassey's  Publishers, 2003): 507–514.</ref>  It assumes that the careers of similar players will follow a similar trajectory.<ref>{{cite web|url=http://baseballprospectus.com/|title=Baseball Prospectus|access-date=2012-03-04}}</ref>

Beginning in the 2007 baseball season, MLB started looking at technology to record detailed information regarding each pitch that is thrown in a game. This became known as the [[PITCHf/x]] system, which uses video cameras to record pitch speed at its release point and crossing the plate, location, and angle (if any) of a break.<ref name=":12"/> 

[[FanGraphs]] is a website that utilizes this information and other play-by-play data to publish advanced baseball statistics and graphics.<ref>{{Cite web |title=FanGraphs Baseball {{!}} Baseball Statistics and Analysis |url=https://www.fangraphs.com/ |access-date=2024-05-26 |website=FanGraphs Baseball |language=en}}</ref>

== In popular culture ==
* ''[[Moneyball (film)|Moneyball]]'', the 2011 film about [[Billy Beane]]'s use of sabermetrics to build the [[Oakland Athletics]]. The film is based on [[Michael Lewis]]'s [[Moneyball: The Art of Winning an Unfair Game|book of the same name]].
* In the television show ''[[Numb3rs]]'', the [[Numbers (season 3)|season 3]] episode "Hardball" focuses on sabermetrics, and the [[Numbers (season 1)|season 1]] episode "Sacrifice" also covers the subject.
* "[[MoneyBART]]", the third episode of ''[[The Simpsons]]''{{'}} [[The Simpsons (season 22)|22nd season]], in which [[Lisa Simpson|Lisa]] utilizes sabermetrics to coach [[Bart Simpson|Bart's]] [[Little League Baseball]] team.

== See also ==
{{Portal|Baseball}}
<!--EDITORS: do not include any terms that already appear in the main text-->
{{div col}}
* [[Analytics (ice hockey)]], the ice hockey equivalent
* [[Advanced statistics in basketball]], the basketball equivalent
* [[Fielding Bible Award]]
* [[Kyle Boddy]], founder of Driveline Baseball
* [[Statcast]]
* ''[[The Hardball Times]]''
* [[Theorycraft]]
* ''[[Total Baseball]]'' by [[John Thorn]] and [[Pete Palmer]]
* ''[[Whatever Happened to the Hall of Fame?]]'' by Bill James
{{div col end}}

==Notes==
{{notelist}}

== References ==
{{Reflist|30em}}

== External links ==
{{wiktionary}}
* [http://www.sabr.org/ Society for American Baseball Research] (SABR)

{{Baseball statistics}}
{{Sports rating systems}}

[[Category:Baseball statistics]]
[[Category:Baseball strategy]]
[[Category:Bill James]]
[[Category:Sports science]]
[[Category:Society for American Baseball Research]]