Baseball statistics


Baseball statistics play an important role in evaluating the progress of a player or team.
Since the flow of a baseball game has natural breaks to it, and normally players act individually rather than performing in clusters, the sport lends itself to easy record-keeping and statistics. Statistics have been kept for professional baseball since the creation of the National League and American League, now part of Major League Baseball.
Many statistics are also available from outside Major League Baseball, from leagues such as the National Association of Professional Base Ball Players and the Negro Leagues, although the consistency of whether these records were kept, of the standards with respect to which they were calculated, and of their accuracy has varied.

Development

The practice of keeping records of player achievements was started in the 19th century by 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".

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.

Batting statistics

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 2015 seasons, the following tables show top ranges in various statistics, in alphabetical order. For each statistic, two values are given:

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