In baseball statistics, earned run average (ERA) is the mean of earned runs given up by a pitcher per nine innings pitched. It is determined by dividing the number of earned runs allowed by the number of innings pitched and multiplying by nine. Runs resulting from defensive errors (including pitchers' defensive errors) are recorded as unearned runs and are not used to determine ERA.

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Henry Chadwick is credited with first devising the statistic, which caught on as a measure of pitching effectiveness after relief pitching came into vogue in the 1900s. Prior to 1900 – and, in fact, for many years afterward – pitchers were routinely expected to pitch a complete game, and their win-loss record was considered sufficient in determining their effectiveness.

Some means had to be found to determine and calculate the apportionment of earned-run responsibility where multiple pitchers have performed in a single game. Since pitchers have sole responsibility to put opposing batters out, they must assume responsibility when a batter they do not retire at the plate moves to base, and eventually reaches home, scoring a run. A pitcher is assessed an earned run for each earned run scored by a batter (or pinch-runner) who reached base while batting against that pitcher. After pitchers like James Otis Crandall and Charlie Hall made names for themselves as relief specialists, gauging a pitcher's effectiveness became more difficult using the traditional method of tabulating wins and losses. The National League first kept official earned run average statistics in 1912 (the statistic was called "Heydler's statistic" for a while, after then-NL secretary John Heydler), with the American League following suit afterward.

George Timothy Clooney (born May 6, 1961) is an American actor, film director, producer, and screenwriter. For his work as an actor, he has received three Golden Globe Awards and an Academy Award. Clooney is also noted for his political activism, and has served as one of the United Nations Messengers of Peace since January 31, 2008.

Though he made his acting debut on television in 1978, Clooney gained fame and recognition by portraying Dr. Douglas "Doug" Ross on the long-running medical drama ER from 1994 to 1999. While working on ER, he started attracting a variety of leading roles in films including Batman & Robin (1997) and Out of Sight (1998), in which he first teamed with long-term collaborator Steven Soderbergh. 1999 saw the release of Three Kings, a well-received war satire set during the Gulf War featuring Clooney in another lead role. In 2001, Clooney's fame widened with the release of his biggest commercial success, Ocean's Eleven, the first of a profitable film trilogy, a remake of the film from 1960 with the members of The Rat Pack with Frank Sinatra as Danny Ocean. He made his directorial debut a year later with the 2002 biographical thriller Confessions of a Dangerous Mind, and has since directed Good Night, and Good Luck (2005), Leatherheads (2008), and The Ides of March (2011). He won an Academy Award for Best Supporting Actor for his work in the Middle East thriller Syriana (2005) and subsequently fetched Best Actor nominations for such films as Michael Clayton (2007), Up in the Air (2009) and The Descendants (2011).