Traditionally, statistics such as batting average (the number of hits divided by the number of at bats) and earned run average (the average number of earned runs allowed by a pitcher per nine innings) have dominated attention in the statistical world of baseball. However, the recent advent of sabermetrics has created statistics drawing from a greater breadth of player performance measures and playing field variables. Sabermetrics and comparative statistics attempt to provide an improved measure of a player's performance and contributions to his team from year to year, frequently against a statistical performance average.
Comprehensive, historical baseball statistics were difficult for the average fan to access until 1951, when researcher Hy Turkin published The Complete Encyclopedia of Baseball. In 1969, Macmillan Publishing printed its first Baseball Encyclopedia, using a computer to compile statistics for the first time. Known as "Big Mac", the encyclopedia became the standard baseball reference until 1988, when Total Baseball was released by Warner Books using more sophisticated technology. The publication of Total Baseball led to the discovery of several "phantom ballplayers", such as Lou Proctor, who did not belong in official record books and were removed.
Use of statistics
Throughout modern baseball, a few core statistics have been traditionally referenced – batting average, RBI, and home runs. To this day, a player who leads the league in all of these three statistics earns the "Triple Crown." For pitchers, wins, ERA, and strikeouts are the most often-cited statistics, and a pitcher leading his league in these statistics may also be referred to as a "Triple Crown" winner. General managers and baseball scouts have long used the major statistics, among other factors and opinions, to understand player value. Managers, catchers and pitchers use the statistics of batters of opposing teams to develop pitching strategies and set defensive positioning on the field. Managers and batters study opposing pitcher performance and motions in attempting to improve hitting.
Some sabermetric statistics have entered the mainstream baseball world that measure a batter's overall performance including on-base plus slugging, commonly referred to as OPS. OPS adds the hitter's on-base percentage (number of times reached base by any means divided by total plate appearances) to his slugging percentage (total bases divided by at-bats). Some argue that the OPS formula is flawed and that more weight should be shifted towards OBP (on-base percentage). The statistic wOBA (weighted on-base average) attempts to correct for this.
OPS is also useful when determining a pitcher's level of success. "Opponent On-base Plus Slugging" (OOPS) is becoming a popular tool to evaluate a pitcher's actual performance. When analyzing a pitcher's statistics, some useful categories to consider include K/9IP (strikeouts per nine innings), K/BB (strikeouts per walk), HR/9 (Home runs per nine innings), WHIP (walks plus hits per inning pitched) and OOPS (opponent on-base plus slugging).
However, since 2001, more emphasis has been placed on Defense-Independent Pitching Statistics, including Defense-Independent ERA (dERA), in an attempt to evaluate a pitcher's performance regardless of the strength of the defensive players behind him.
All of the above statistics may be used in certain game situations. For example, a certain hitter's ability to hit left-handed pitchers might incline a manager to increase his opportunities to face left-handed pitchers. Other hitters may have a history of success against a given pitcher (or vice versa), and the manager may use this information to create a favorable match-up. Broadcast commentators often refer to this as "playing the percentages".
Commonly used statistics
Most of these terms also apply to softball. Commonly used statistics with their abbreviations are explained here. The explanations below are for quick reference and do not fully or completely define the statistic; for the strict definition, see the linked article for each statistic.
1B – Single: hits on which the batter reaches first base safely without the contribution of a fielding error.
2B – Double: hits on which the batter reaches second base safely without the contribution of a fielding error.
3B – Triple: hits on which the batter reaches third base safely without the contribution of a fielding error.
AB – At bat: Plate appearances, not including bases on balls, being hit by pitch, sacrifices, interference, or obstruction.
IBB – Intentional base on balls: times awarded first base on balls (see BB above) deliberately thrown by the pitcher. Also known as IW (intentional walk).
ISO – Isolated power: a hitter's ability to hit for extra bases, calculated by subtracting batting average from slugging percentage
K – Strike out (also abbreviated SO): number of times that a third strike is taken or swung at and missed, or bunted foul. Catcher must catch the third strike or batter may attempt to run to first base.
LOB – Left on base: number of runners neither out nor scored at the end of an inning.
OBP – On-base percentage: times reached base (H + BB + HBP) divided by at bats plus walks plus hit by pitch plus sacrifice flies (AB + BB + HBP + SF).
TA – Total average: total bases, plus walks, plus hit by pitch, plus steals, minus caught stealing divided by at bats, minus hits, plus caught stealing, plus grounded into double plays [(TB + BB + HBP + SB - CS)/(AB - H + CS + GIDP)]
TB – Total bases: one for each single, two for each double, three for each triple, and four for each home run [H + 2B + (2 * 3B) + (3 * HR)] or [1B + (2 * 2B) + (3 * 3B) + (4 * HR)]
TOB – Times on base: times reaching base as a result of hits, walks, and hit-by-pitches (H + BB + HBP)
L – Loss: number of games where pitcher was pitching while the opposing team took the lead, never lost the lead, and went on to win
LOB% – Left-on-base percentage: LOB% represents the percentage of baserunners a pitcher does not allow to score. LOB% tends to regress toward 70–72% over time, so unusually high or low percentages could indicate that pitcher's ERA could be expected to rise or lower in the future. An occasional exception to this logic is a pitcher with a very high strikeout rate.
SV – Save: number of games where the pitcher enters a game led by the pitcher's team, finishes the game without surrendering the lead, is not the winning pitcher, and either (a) the lead was three runs or fewer when the pitcher entered the game; (b) the potential tying run was on base, at bat, or on deck; or (c) the pitcher pitched three or more innings
SVO – Save opportunity: When a pitcher 1) enters the game with a lead of three or fewer runs and pitches at least one inning, 2) enters the game with the potential tying run on base, at bat, or on deck, or 3) pitches three or more innings with a lead and is credited with a save by the official scorer
W – Win: number of games where pitcher was pitching while his team took the lead and went on to win, also the starter needs to pitch at least 5 innings of work (also related: winning percentage)
whiff rate: a term, usually used in reference to pitchers, that divides the number of pitches swung at and missed by the total number of swings in a given sample. If a pitcher throws 100 pitches at which batters swing, and the batters fail to make contact on 26 of them, the pitcher's whiff rate is 26%.
It is difficult to determine quantitatively what is considered to be a "good" value in a certain statistical category, and qualitative assessments may lead to arguments. Using full-season statistics available at the Official Site of Major League Baseball for the 2004 through 2011 seasons, the following tables show top ranges in various statistics, in alphabetical order. For each statistic, two values are given:
Top5: the top five players bettered this value in all of the reported seasons
Best: this is the best of all of the players for all of the reported seasons
^Palmer, Pete; Paul Adomites; David Nemec; Matthew D. Greenberger; Dan Schlossberg; Dick Johnson; Mike Tully (2001). "Birth of the Game". Cooperstown: Hall of Fame Players. Lincolnwood, Illinois: Publications International. p. 21. ISBN0-7853-4530-2.
^ abPete Palmer and Gary Gillette, ed. (2005). "Introduction". The 2005 ESPN Baseball Encyclopedia (1st Edition ed.). New York: Sterling. ISBN1-4027-2568-X.