Batting average

Batting average is defined as the ratio of hits to at bats.

The Major League Baseball batting average championship 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.

First devised by Henry Chadwick in the 19th century, batting average is a measure of a player's ability to hit. In modern times, a batting average over .300 is considered to be good, and an average over .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).

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 for Mario Mendoza, a stellar defensive shortstop who hit .215 over his Major League career. The league batting average in Major League Baseball is currently (2001) in the range of .260 to 275.

Sabermetrics considers batting average a weak measure of performance because it does not correlate as well as other measures to runs scored. BA does not take into account walks or power.

The decline of the .400 hitter

Many scientists believe that the range of a given species will tend to decrease over time. That is, the average difference between the tallest and shortest members of a species will tend to decline over time; the difference between the fastest-running and the slowest members will tend to decline; and so on.

In the same way, as biologist and baseball fan Stephen Jay Gould argued in one article, in baseball the difference between the strongest hitters and the weakest hitters has declined over time. Not only has the .400 hitter disappeared; so has the .150 hitter. Thus the evolution of baseball players can be said to mimic other evolutionary groups.

See also: Baseball statistics