Editing Sabermetrics (section)

=== 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.