Component ERA or ERC is a

baseball Baseball is a bat-and-ball sport played between two teams of nine players each, taking turns batting and fielding. The game occurs over the course of several plays, with each play generally beginning when a player on the fielding tea ...

statistic invented by

Bill James George William James (born October 5, 1949) is an American baseball writer, historian, and statistician whose work has been widely influential. Since 1977, James has written more than two dozen books devoted to baseball history and statistics. ...

. It attempts to forecast a pitcher's

earned run average In baseball statistics, earned run average (ERA) is the average of earned runs allowed by a pitcher per nine innings pitched (i.e. the traditional length of a game). It is determined by dividing the number of earned runs allowed by the number ...

(ERA) from the number of hits and walks allowed rather than the standard formula of average number of earned runs per nine innings. ERC allows one to take a fresh look at a pitcher's performance and gauge if his results are more or less than the sum of its parts. The formula for ERC as it appears in the 2004 edition of the Bill James Handbook:

ERC = 9 *  - 0.56

where H is

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, BB is

bases on balls A base on balls (BB), also known as a walk, occurs in baseball when a batter receives four pitches that the umpire calls '' balls'', and is in turn awarded first base without the possibility of being called out. The base on balls is defined in Se ...

(walks), HBP is

hit by pitch In baseball, hit by pitch (HBP) is an event in which a batter or his clothing or equipment (other than his bat) is struck directly by a pitch from the pitcher; the batter is called a hit batsman (HB). A hit batsman is awarded first base, provided ...

, BFP is

batters faced by pitcher In baseball statistics, Batters Faced (BF), also known as Total Batters Faced (TBF) or Batters Facing Pitcher (BFP) is the number of batters who made a plate appearance before the pitcher in a game or in a season. For a given game, the number of p ...

, IP is

innings pitched In baseball, innings pitched (IP) are the number of innings a pitcher has completed, measured by the number of batters and baserunners that are put out while the pitcher is on the pitching mound in a game. Three outs made is equal to one innin ...

, and PTB is pitcher's total bases and is defined as:

PTB = 0.89 * (1.255*(H-HR) + 4*HR) + 0.56 * (BB + HBP -IBB)

where HR is

home run In baseball, a home run (abbreviated HR) is scored when the ball is hit in such a way that the batter is able to circle the bases and reach home plate safely in one play without any errors being committed by the defensive team. A home run i ...

s, IBB is

intentional walk In baseball, an intentional base on balls, usually referred to as an intentional walk and denoted in baseball scorekeeping by ''IBB'', is a walk issued to a batter by a pitcher with the intent of removing the batter's opportunity to swing at the ...

s, and others are as above. The point of the first component is to represent the number of baserunners allowed. The PTB component combines an estimate of extra bases allowed (first half) with the fact that walks and hit by pitches do not advance unforced baserunners (second half). The division places the computation into an ERA context, and the final subtraction moves that scale down into its normal range. Where intentional walk data are not available use:

PTB = 0.89 * (1.255*(H-HR) + 4*HR) + 0.475 * (BB + HBP)

If ERC is less than 2.24, the formula is adjusted as follows:

ERC = 9 *  * 0.75

Other people and organizations have their own proprietary formulae for ERC which may correlate more highly with actual earned runs scored than the formula above. Component ERA was added to the

ESPN.com ESPN.com is the official website of ESPN. It is owned by ESPN Internet Ventures, a division of ESPN Inc. History Since launching in April 1995 as ESPNET.SportsZone.com (ESPNET SportsZone), the website has developed numerous sections including: ...

"Sortable Stats" in 2004.

See also