View source for WOBA

{{Short description|Baseball statistic}}
{{lowercase}}
In [[baseball]], '''wOBA''' (or weighted on-base average)<ref>{{Cite web|url=https://www.fangraphs.com/blogs/the-language-of-fangraphs/|title=The Language Of Fangraphs {{!}} FanGraphs Baseball|date=11 January 2010 |access-date=2018-12-07}}</ref> is a statistic, based on [[Linear regression|linear weights]],<ref>{{cite web|url=https://www.fangraphs.com/library/principles/linear-weights/|title=Linear Weights - FanGraphs Sabermetrics Library|website=www.fangraphs.com}}</ref> 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]]. Unlike statistics like [[On-base plus slugging|OPS]], wOBA attempts to assign the proper value for each type of hitting event. It was created by [[Tom Tango]] and his coauthors for ''The Book: Playing the Percentages in Baseball''.<ref name="thebook">{{cite web|url=http://www.insidethebook.com/woba.shtml|title=wOBA - Weighted On Base Average|website=www.insidethebook.com}}</ref>

== Usage ==

In 2008, [[sabermetrics]] website [[FanGraphs]] began listing the current and historical wOBA for all players in [[Major League Baseball]].<ref>{{cite web|url=http://www.fangraphs.com/blogs/index.php/the-joy-of-woba/|title=The Joy of wOBA - FanGraphs Baseball|website=www.fangraphs.com|date=25 November 2008 }}</ref> It forms the basis of the offensive component of their [[wins above replacement]] (WAR) metric. Sites such as [[The Hardball Times]] have studied wOBA and found it to perform comparably to or better than other similar tools ([[On-base plus slugging|OPS]], [[Runs created|RC]], etc.) used in sabermetrics to estimate runs.<ref>{{cite web|url=https://www.fangraphs.com/tht/the-great-run-estimator-shootout-part-1/|title=The great run estimator shootout (part 1) - The Hardball Times|website=www.fangraphs.com|date=9 April 2009 }}</ref><ref>{{cite web|url=https://www.fangraphs.com/tht/the-great-run-estimator-shootout-part-2/|title=The great run estimator shootout (part 2) - The Hardball Times|website=www.fangraphs.com}}</ref> ''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''.<ref>{{Cite web|url=http://m.mlb.com/glossary/advanced-stats/weighted-on-base-average|title=What is a Weighted On-base Average (wOBA)? {{!}} Glossary|website=Major League Baseball|language=en-US|access-date=2018-11-09}}</ref><ref>{{Cite web|url=https://www.fangraphs.com/library/offense/woba/|title=wOBA {{!}} FanGraphs Sabermetrics Library|website=www.fangraphs.com|access-date=2018-11-09}}</ref> 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<ref name=":0">{{Cite web |title=Guts! |url=https://www.fangraphs.com/guts.aspx?type=cn |access-date=November 9, 2018 |website=FanGraphs}}</ref> 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.<ref name=":1" />

Balls hit hard (i.e. with a high [[exit velocity]]) in the [[sweet spot (sports)|sweet spot]] produce higher wOBA.<ref>{{cite news|first=Ben|last=Clemens|title=A Sweet Spot by Any Other Definition|date=February 25, 2020|work=FanGraphs|url=https://blogs.fangraphs.com/a-sweet-spot-by-any-other-definition/|access-date=March 14, 2024}}</ref>

== Historical versions of the formula ==
Coefficients for each tracked outcome vary by year. A historical record of these coefficients can be found at FanGraphs.<ref name=":0" />

=== 2023 ===
Per [[Fangraphs]], the formula for wOBA in the 2023 season was:<ref name=":0" />

<math>wOBA=\frac{(0.697*NIBB) + (0.727*HBP) + (0.855*\mathit{1}B) + (1.248*\mathit{2}B) + (1.575*\mathit{3}B) + (2.014*HR)}{AB + BB - IBB + SF + HBP}
 </math>

where:
* ''NIBB'' = ''[[Base on balls|<u>Non-intentional</u> bases on balls]]''
* ''HBP'' = ''[[Hit by pitch]]''
* ''1B'' = ''[[Single (baseball)|Single]]''
* ''2B'' = ''[[Double (baseball)|Double]]''
* ''3B'' = ''[[Triple (baseball)|Triple]]''
* ''HR'' = ''[[Home run]]''

—————

* ''AB'' = ''[[At bat]]''
* ''BB'' = ''[[Base on balls|Bases on balls]]''
* ''IBB'' = ''[[base on balls#Intentional base on balls|<u>Intentional</u> bases on balls]]''
* ''SF'' = ''[[Sacrifice fly|Sacrifice flies]]''
* ''HBP'' = ''[[Hit by pitch]]''

=== Original formula ===
The formula below appeared in ''The Book.''<ref>{{Cite book |last=Tango, Tom M. |url=https://www.worldcat.org/oclc/919473395 |title=The book : playing the percentages in baseball |others=Lichtman, Mitchel G., Dolphin, Andrew E. |date=28 April 2014 |isbn=978-1-4942-6017-0 |location=[Place of publication not identified] |oclc=919473395}}</ref>

<math>wOBA=\frac{(0.72*NIBB) + (0.75*HBP) + (0.90*\mathit{1}B) + (0.92*RBOE) + (1.24*\mathit{2}B) + (1.56*\mathit{3}B) + (1.95*HR)}{PA}</math>

where:
* ''NIBB'' = Non-intentional [[Base on balls|bases on balls]]
* ''HBP'' = [[Hit by pitch]]
* ''1B'' = [[Single (baseball)|Single]]
* ''RBOE'' = Reached base on [[Error (baseball)|error]]
* ''2B'' = [[Double (baseball)|Double]]
* ''3B'' = [[Triple (baseball)|Triple]]
* ''HR'' = [[Home run]]
* ''PA'' = [[Plate appearance]]

== Ranges for elite, very good, etc. ==

The following table serves as an aggregate summary of various wOBA scales available online.<ref name=":1">{{Cite web|url=https://www.blessyouboys.com/2010/1/19/1258772/saber-101-weighted-on-base-average|title=Saber 101: Weighted On-Base Average (wOBA)|last=Rogers|first=Mike|date=2010-01-19|website=Bless You Boys|access-date=2018-12-07}}</ref><ref>{{Cite web|url=https://www.fangraphs.com/library/the-beginners-guide-to-deriving-woba/|title=The Beginner's Guide To Deriving wOBA {{!}} FanGraphs Sabermetrics Library|date=11 April 2016 |access-date=2018-12-07}}</ref>
{| class="wikitable"
|+wOBA Scale
!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 ==

<!-- See http://en.wikipedia.org/wiki/Wikipedia:Footnotes on how to create references using tags which will then appear here automatically -->
{{Reflist}}

== References ==

* [[Tom Tango]], Mitchel Lichtman, and Andrew Dolphin. ''The Book: Playing the Percentages in Baseball''. Washington, D.C.: Potomac Books, 2007. {{ISBN|1-59797-129-4}}.

{{Baseball statistics}}

[[Category:Batting statistics]]