Baseball statistics


Baseball statistics collect a variety of metrics used to evaluate player and team performance in the sport of baseball.
Because the flow of a baseball game has natural breaks, and player performance is individually measurable, the sport lends itself to easy record-keeping and compiling statistics. Baseball "stats" have been recorded since the game's beginnings as a sport in the middle of the nineteenth century, and are widely available through the historical records of leagues such as the National Association of Professional Base Ball Players and the Negro leagues, although the consistency, standards, and calculations are often incomplete or questionable.
Since the National League was founded in 1876, statistics in the most elite levels of professional baseball have been kept, with efforts to standardize the stats and their compilation improving during the early 20th century. Such efforts have evolved together with advances in technology ever since. The NL was joined by the American League in 1903; together the two constitute modern Major League Baseball. A number of statistics are defined in the Official Baseball Rules, which task the official scorer with providing a report after each game.
Advances in both statistical analysis and technology made possible by the "PC revolution" of the 1980s and 1990s have driven teams and fans to evaluate players by an ever more elaborate set of statistics, which hold them to ever-evolving standards. With the advent of these methods, players can be compared across different eras and run scoring environments.

Development

The practice of keeping records of player achievements was started in the 19th century by English-American sportswriter Henry Chadwick. Based on his experience with the sport of cricket, Chadwick devised the predecessors to modern-day statistics including batting average, runs scored, and runs allowed.
Traditionally, statistics such as batting average and earned run average 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

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. Scouts use stats when they are looking at a player who they may end up drafting or signing to a contract.
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 to their slugging percentage. Some argue that the OPS formula is flawed and that more weight should be shifted towards OBP. The statistic wOBA attempts to correct for this.
OPS is also useful when determining a pitcher's level of success. "Opponent on-base plus slugging" is becoming a popular tool to evaluate a pitcher's actual performance. When analyzing a pitcher's statistics, some useful categories include K/9IP, K/BB, HR/9, WHIP, and OOPS.
However, since 2001, more emphasis has been placed on defense-independent pitching statistics, including defense-independent ERA, in an attempt to evaluate a pitcher's performance regardless of the strength of the defensive players behind them.
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 their opportunities to face left-handed pitchers. Other hitters may have a history of success against a given pitcher, and the manager may use this information to create a favorable
match-up. This is often referred to as "playing the percentages".

Contemporary statistics

The following listings include abbreviations and/or acronyms for both historic baseball statistics and those based on modern mathematical formulas known popularly as "metrics".
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.

Batting statistics

  • 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
  • AB/HR – At bats per home run: at bats divided by home runs
  • BA – Batting average : hits divided by at bats
  • BB – Base on balls : hitter not swinging at four pitches called out of the strike zone and awarded first base.
  • BABIP – Batting average on balls in play: frequency at which a batter reaches a base after putting the ball in the field of play. Also a pitching category.
  • BB/K – Walk-to-strikeout ratio: number of bases on balls divided by number of strikeouts
  • BsR – Base runs: Another run estimator, like runs created
  • EQA – Equivalent average: a player's batting average absent park and league factors
  • FC – Fielder's choice: times reaching base safely because a fielder chose to try for an out on another runner
  • GO/AO – Ground ball fly ball ratio: number of ground ball outs divided by number of fly ball outs
  • GDP or GIDP – Ground into double play: number of ground balls hit that became double plays
  • GPA – Gross production average: 1.8 times on-base percentage plus slugging percentage, divided by four
  • GS – Grand slam: a home run with the bases loaded, resulting in four runs scoring, and four RBIs credited to the batter
  • H – Hit: reaching base because of a batted, fair ball without error by the defense
  • HBP – Hit by pitch: times touched by a pitch and awarded first base as a result
  • HR – Home runs: hits on which the batter successfully touched all four bases, without the contribution of a fielding error
  • HR/H – Home runs per hit: home runs divided by total hits
  • ITPHR – Inside-the-park home run: hits on which the batter successfully touched all four bases, without the contribution of a fielding error or the ball going outside the ball park.
  • IBB – Intentional base on balls: times awarded first base on balls deliberately thrown by the pitcher. Also known as IW.
  • ISO – Isolated power: a hitter's ability to hit for extra bases, calculated by subtracting batting average from slugging percentage
  • K – Strike out : 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 divided by at bats plus walks plus hit by pitch plus sacrifice flies
  • OPS – On-base plus slugging: on-base percentage plus slugging average
  • PA – Plate appearance: number of completed batting appearances
  • PA/SO – Plate appearances per strikeout: number of times a batter strikes out to their plate appearance
  • R – Runs scored: number of times a player crosses home plate
  • RC – Runs created: an attempt to measure how many runs a player has contributed to their team
  • RP – Runs produced: an attempt to measure how many runs a player has contributed
  • RBI – Run batted in: number of runners who score due to a batter's action, except when the batter grounded into a double play or reached on an error
  • RISP – Runner in scoring position: a breakdown of a batter's batting average with runners in scoring position, which includes runners at second or third base
  • SF – Sacrifice fly: fly balls hit to the outfield which, although caught for an out, allow a baserunner to advance
  • SH – Sacrifice hit: number of sacrifice bunts which allow runners to advance on the basepaths
  • SLG – Slugging percentage: total bases achieved on hits divided by at-bats
  • 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 – Total bases: one for each single, two for each double, three for each triple, and four for each home run or
  • TOB – Times on base: times reaching base as a result of hits, walks, and hit-by-pitches
  • XBH – Extra base hits: total hits greater than singles