Component ERA
Encyclopedia
Component ERA or ERC is a baseball
statistic invented by Bill James
. It attempts to forecast a pitcher's earned run average
(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:
where H is hits
, BB is bases on balls (walks), HBP is hit by pitch
, BFP is batters faced by pitcher
, IP is innings pitched
, and PTB is defined as:
where HR is home run
s, IBB is intentional walks, and others are as above.
Where intentional walk data are not available use:
If ERC is less than 2.24, the formula is adjusted as follows:
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
"Sortable Stats" in 2004.
Baseball
Baseball is a bat-and-ball sport played between two teams of nine players each. The aim is to score runs by hitting a thrown ball with a bat and touching a series of four bases arranged at the corners of a ninety-foot diamond...
statistic invented by Bill James
Bill James
George William “Bill” James is a 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
Earned run average
In baseball statistics, earned run average 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...
(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 = (((H + BB + HBP)×PTB)/(BFP×IP))×9 − 0.56
where H is hits
Hit (baseball)
In baseball statistics, a hit , also called a base hit, is credited to a batter when the batter safely reaches first base after hitting the ball into fair territory, without the benefit of an error or a fielder's choice....
, BB is bases on balls (walks), HBP is hit by pitch
Hit by pitch
In baseball, hit by pitch , or hit batsman , is a batter or his equipment being hit in some part of his body by a pitch from the pitcher.-Official rule:...
, BFP is batters faced by pitcher
Batters Faced by Pitcher
In baseball statistics, Batters Faced by Pitcher , also known as Total Batters Faced , is the number of batters who made a plate appearance before the pitcher in a game or in a season....
, IP is innings pitched
Innings pitched
In baseball, innings pitched are the number of innings a pitcher has completed, measured by the number of batters and baserunners that are put out while the pitcher on the pitching mound in a game. Three outs made is equal to one inning pitched. One out counts as one-third of an inning, and two...
, and PTB is defined as:
- PTB = 0.89×(1.255×(H − HR) + 4×HR) + 0.56×(BB + HBP − IBB)
where HR is home run
Home run
In baseball, a home run is scored when the ball is hit in such a way that the batter is able to reach home safely in one play without any errors being committed by the defensive team in the process...
s, IBB is intentional walks, and others are as above.
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 = (((H + BB + HBP)×PTB)/(BFP×IP))×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
ESPN.com is the official website of ESPN and a division of ESPN Inc. Since launching in 1995 as ESPNet.SportsZone.com, the website has developed numerous sections including: Page 2, SportsNation, ESPN 3.com, ESPN Motion, My ESPN, ESPN Sports Travel, ESPN Video Games, ESPN Insider, ESPN.com's...
"Sortable Stats" in 2004.
See also
- Earned Run AverageEarned run averageIn baseball statistics, earned run average 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...
- DIPSDefense independent pitching statisticsIn baseball, defense-independent pitching statistics measure a pitcher's effectiveness based only on plays that do not involve fielders: home runs allowed, strikeouts, hit batters, walks, and, more recently, fly ball percentage, ground ball percentage, and line drive percentage...
- WHIPWalks plus hits per inning pitchedIn baseball statistics, walks plus hits per inning pitched is a sabermetric measurement of the number of baserunners a pitcher has allowed per inning pitched. It is a measure of a pitcher's ability to prevent batters from reaching base...