wOBA
Inbaseball,wOBA(or weighted on-base average)[1]is a statistic, based onlinear weights,[2]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 ason-base percentage.Unlike statistics likeOPS,wOBA attempts to assign the proper value for each type of hitting event. It was created byTom Tangoand his coauthors forThe Book: Playing the Percentages in Baseball.[3]
Usage
[edit]In 2008,sabermetricswebsiteFanGraphsbegan listing the current and historical wOBA for all players inMajor League Baseball.[4]It forms the basis of the offensive component of theirwins above replacement(WAR) metric. Sites such asThe Hardball Timeshave studied wOBA and found it to perform comparably to or better than other similar tools (OPS,RC,etc.) used in sabermetrics to estimate runs.[5][6]The Bookuses 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 justwhetherthe runner reached base buthow.[7][8]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[9]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.[10]
Balls hit hard (i.e. with a highexit velocity) in thesweet spotproduce higher wOBA.[11]
Historical versions of the formula
[edit]Coefficients for each tracked outcome vary by year. A historical record of these coefficients can be found at FanGraphs.[9]
2023
[edit]PerFangraphs,the formula for wOBA in the 2023 season was:[9]
where:
- NIBB=Non-intentionalbases on balls
- HBP=Hit by pitch
- 1B=Single
- 2B=Double
- 3B=Triple
- HR=Home run
—————
- AB=At bat
- BB=Bases on balls
- IBB=Intentionalbases on balls
- SF=Sacrifice flies
- HBP=Hit by pitch
Original formula
[edit]The formula below appeared inThe Book.[12]
where:
- NIBB= Non-intentionalbases on balls
- HBP=Hit by pitch
- 1B=Single
- RBOE= Reached base onerror
- 2B=Double
- 3B=Triple
- HR=Home run
- PA=Plate appearance
Ranges for elite, very good, etc.
[edit]The following table serves as an aggregate summary of various wOBA scales available online.[10][13]
Classification | Range |
---|---|
Elite | .400 and Above |
Very Good | .371 to.399 |
Good | .321 to.370 |
Average | .320 |
Bad | .291 to.320 |
Very Bad | .290 and below |
Citations
[edit]- ^"The Language Of Fangraphs | FanGraphs Baseball".11 January 2010.Retrieved2018-12-07.
- ^"Linear Weights - FanGraphs Sabermetrics Library".www.fangraphs.com.
- ^"wOBA - Weighted On Base Average".www.insidethebook.com.
- ^"The Joy of wOBA - FanGraphs Baseball".www.fangraphs.com.25 November 2008.
- ^"The great run estimator shootout (part 1) - The Hardball Times".www.fangraphs.com.9 April 2009.
- ^"The great run estimator shootout (part 2) - The Hardball Times".www.fangraphs.com.
- ^"What is a Weighted On-base Average (wOBA)? | Glossary".Major League Baseball.Retrieved2018-11-09.
- ^"wOBA | FanGraphs Sabermetrics Library".www.fangraphs.com.Retrieved2018-11-09.
- ^abc"Guts!".FanGraphs.RetrievedNovember 9,2018.
- ^abRogers, Mike (2010-01-19)."Saber 101: Weighted On-Base Average (wOBA)".Bless You Boys.Retrieved2018-12-07.
- ^Clemens, Ben (February 25, 2020)."A Sweet Spot by Any Other Definition".FanGraphs.RetrievedMarch 14,2024.
- ^Tango, Tom M. (28 April 2014).The book: playing the percentages in baseball.Lichtman, Mitchel G., Dolphin, Andrew E. [Place of publication not identified].ISBN978-1-4942-6017-0.OCLC919473395.
{{cite book}}
:CS1 maint: location missing publisher (link) - ^"The Beginner's Guide To Deriving wOBA | FanGraphs Sabermetrics Library".11 April 2016.Retrieved2018-12-07.
References
[edit]- Tom Tango,Mitchel Lichtman, and Andrew Dolphin.The Book: Playing the Percentages in Baseball.Washington, D.C.: Potomac Books, 2007.ISBN1-59797-129-4.