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Batting average is a statistic in both baseball and cricket measuring the performance of baseball hitters and cricket batsmen, respectively. The two statistics are related, in that baseball averages are directly descended from the concept of cricket averages.
The term batting average is also used in non-sporting contexts to represent various statistical measures of performance.
Cricket
In cricket, a player's batting average is the total number of runs he has scored divided by the number of times he has been out. Since the number of runs a player scores and how often he gets out are primarily measures of his own playing ability, and largely independent of his team mates, batting average is a good statistic for describing an individual player's skill as a batsman. The number is also simple to interpret intuitively, being approximately the average number of runs the batsman scores per innings. Batting average has been used to gauge cricket players' relative skills since the 18th century.
Most players have batting averages in the range 10 to 50:
- Between 30 and 50 is typical for specialist batsmen and genuine all-rounders . This is also the desirable range for wicket-keepers, though some fall short and make up for it with fielding skill.
- All-rounders who are in practice more prominent bowlers than batsmen typically average something between 20 and 30.
- 15 and under is typical for specialist bowlers.
Career records for batting average are usually subject to a minimum qualification of at least 20 innings played. This is because it is easy to sustain an artificially high average over a career spanning few matches. Under this qualification, the highest Test batting average belongs to Australia's Sir Donald Bradman, with 99.94. Given that a career batting average over 50 is exceptional, and that only three other players have averages (barely) over 60, this is an outstanding statistic. The fact that Bradman's average is so far above that of any other cricketer has led several statisticians to argue that, statistically at least, he was the greatest sportsman in any sport.
Batting averages in One-day International (ODI) cricket tend to be lower than in Test cricket, because of the need to score runs more quickly and take riskier strokes and the lesser emphasis on building a large innings.
Some cricket followers have noted that the batting average is inflated by the number of not-outs (innings in which the batsman has not been dismissed), and argue that a better measure of a batsman's quality is the number of runs scored divided by the number of innings played. This proposed statistic, sometimes called the "innings average", is not commonly used by cricket fans or commentators. Its essential drawback is that it would deflate the apparent quality of players who are often not out, especially good-quality lower-order batsmen who do not get the chance to bat for as long as those higher up the order.
A different, and more recently developed, statistic which is also used to gauge the effectiveness of batsmen is the strike rate. It measures a different concept however - how quickly the batsman scores - so does not supplant the role of batting average.
See also
Baseball
In baseball, the batting average (BA) is defined as the ratio of hits to at bats.
Henry Chadwick, an English statistician raised on cricket, was an influential figure in the early history of baseball. In the late 19th century he adapted the concept behind the cricket batting average to devise a similar statistic for baseball. Rather than take the naive approach and simply copy cricket's formulation of runs scored divided by outs, he realised that hits divided by at bats would provide a better measure of individual batting ability. This is because of an intrinsic difference between the two sports; scoring runs in cricket is dependent almost only on one's own batting skill, whereas in baseball it is largely dependent on having other good hitters in your team. Chadwick noted that hits are independent of team mates' skills, so used this as the basis for the baseball batting average. His reason for using at bats rather than outs is less obvious, but it leads to the intuitive idea of the batting average being a percentage reflecting how often a batter gets on base, whereas hits divided by outs is not as simple to interpret in real terms.
In modern times, a season batting average higher than .300 is considered to be good, and an average higher than .400 a nearly unachievable goal. The last player to do so, with enough at bats to qualify for the batting championship, was Ted Williams of the Boston Red Sox, who hit .406 in 1941, though the best modern players either threaten to or actually do achieve it occasionally, if only for brief periods of time.
Ty Cobb holds the record for highest career batting average with .366, 8 points higher than Rogers Hornsby who has the second highest average in history at .358. Cobb's career batting average record will probably never be broken, since even the best of modern hitters find it difficult to hit higher than .360 in more than one or two seasons, let alone consistently throughout their entire careers. The record for lowest career batting average for a player with more than 2500 at-bats belongs to Bill Bergen, a catcher who played from 1901 to 1911 and recorded a .170 average in 3,028 career at-bats. The modern-era record for highest batting average for a season is held by Napoleon Lajoie, who hit .426 in 1901, the first year of play for the American League. The modern-era record for lowest batting average for a player that qualified for the batting title is held by Rob Deer, who hit .179 in 1991.
For non-pitchers, a batting average below .250 is poor, and one below .200 is totally unacceptable. This latter level is known as "The Mendoza Line", named either for Mario Mendoza, a stellar defensive shortstop who hit .215 during his Major League career, or for Minnie Mendoza, also a shortstop, who was a long-time minor-league player who finally reached the majors briefly in 1970 at the age of 36 and hit .188 in 16 games. The league batting average in Major League Baseball for 2004 was just higher than .266, and the all-time league average is between .260 and .275.
The Major League Baseball batting average championship (often referred to as "the Batting Title") is awarded to the player in each league who has the highest batting average with at least 3.1 plate appearances per game that his team has played during a season, though if the batting leader fails to meet the minimum number of plate appearances, the remaining plate appearances until qualification (502) will be theoretically be considered outs, and if the batting average is still the highest in the league, he will be awarded the title. Ty Cobb also holds the record for most Batting Titles, winning 12 in his pro career.
Sabermetrics, the study of baseball statistics, considers batting average a weak measure of performance because it does not correlate as well as other measures to runs scored, and because it has little predictive value. Batting average does not take into account walks or power, whereas newer statistics like on-base percentage and slugging percentage have been specifically designed to measure such concepts. Others would say it is the most important measure of the performance of a hitter, since it takes into account his consistency and his ability to perform as an individual independent of what his team mates have done. Measuring individual performance rather than runs scored was in fact Chadwick's goal in devising the statistic.
In 1887, Major League Baseball (which at that time consisted solely of the National League) counted bases on balls as hits. The result was skyrocketed batting averages, including some near .500, and the experiment was abandoned the following season.
The decline of the .400 hitter
A point of interest to baseball followers is that hitting .400 was special and rare feat in the early 20th century. It was accomplished only 13 times between 1900-1941 by 8 players, but has not occurred at all since 1941. Many people have expounded theories on why this is the case.One theory of particular interest was proposed by biologist and baseball fan Stephen Jay Gould, in his book The Spread of Excellence From Plato to Darwin (published as Life's Grandeur: The Spread of Excellence from Plato to Darwin in the U.K.). According to Gould, the disappearance of the .400 batting average does not indicate a decline of baseball skill, but, quite the contrary - an improvement in skill. He suggests that instead of looking at the extreme values (the best and worst hitters), we should be looking at the statistical distribution of the batting average of all hitters. If we do this, Gould notes that the league average of batting averages has stayed constant over the last century (mostly due to rules being changed whenever this average started to change), but the variance has been on a continuous decrease, as all major league baseball players have become better and better, closer and closer to the natural "wall" limiting human athletic performance. As a result of this decreasing variance, the best and worst batting averages came closer to the league average, and the best batting average dropped below .400.
Another way to explain Gould's argument is this: A batter's batting average isn't determined just by the batter's individual skill (like is the case in, say, track and field records), but rather depends on the batter's success against opposing players. In the early 20th century, the variance of baseball player skills was still high, so when the top batters played, they had the opportunity to be opposed by both very good and by mediocre players, and as a result had an opportunity to achieve very high batting averages. As baseball became a more professional "industry", variance in player skill came down, and the best batter found himself opposed by consistently very good players, and as a result was not able to achieve as high a batting average as was possible a century earlier.
Although Gould makes a persuasive argument, his theory does not account for the fact that the highest Test cricket batting averages have remained around 60 since the 19th century (with the single notable exception of Bradman), and the lowest around 10. One may conclude that the evolution of sports statistics over time relies on more factors than simple population statistics.
It is also important to note that pitching strategies have changed dramatically since the era of the .400 hitter. Since the 1950s, pitchers have increasingly tried to strike out hitters, rather than get the hitter to put the ball in play. Hitters also more frequently try to hit home runs, which leads to more strikeouts, but in many cases greater offensive production. Also, it is more acceptable to pitch around strong hitters, and to stop throwing strikes after the first two are thrown in a plate appearance, to try to get the hitter to swing at a ball. Lastly, managers now use many more relievers in an average game. This means that hitters see the same pitcher fewer times in a game (losing the advantage of familiarity), and are more likely to face a fresh pitcher, and even a specialist pitcher brought into a game just to get that specific hitter out.
In general, all of these factors either increase strikeout or walk totals, both of which make it much more difficult to achieve a high ratio of hits to at bats, relative to earlier eras of baseball.
See also
Other contexts
Following from usage in cricket and baseball, batting average has come to be used for other statistical measures of performance.
An example is the Internet Archive, which uses the term in ranking downloads. Its "batting average" indicates the correlation between views of a description page of a downloadable item, and the number of actual downloads of the item. This avoids the effect of popular downloads by volume swamping potentially more focused and useful downloads, producing an arguably more useful ranking.
Baseball statistics | Cricket terminology | Batting (cricket) | Cricket records and statistics
"Batting average"