- Run average
In

baseball statistics ,**run average**(**RA**) refers to measures of the rate at which runs are allowed or scored. For "pitcher s," the run average is the number of runs—earned or unearned—allowed per nine innings. It is calculated using this formula::$mathrm\{RA\}\; =\; 9\; cdot\; frac\{mathrm\{R\{mathrm\{IP$

where

*"R" = Runs

*"IP" =Innings pitched Run average for pitchers differs from the more commonly used

earned run average (ERA) by adding unearned runs to the numerator. This measure is also known as**total run average**(**TRA**) or**runs allowed average**. For "batters," the run average is the number of runs scored per at bat. [*cite web*]

title=Run average

publisher=Baseball GM

url=http://baseballgm.blogspot.com/2007/04/blog-post.html

date=2007-04-18

accessdate=2007-07-28**Run average for pitchers**Although presentations of pitching statistics generally feature the ERA rather than the RA, the latter statistic is notable for both historical and analytical reasons. For early leagues or leagues for which statistics must be calculated from box scores, such as the Negro leagues, data on earned runs may be unavailable and RA may be the only statistic available. [

*Holway, p. 9.*] The analytical case for RA appeared as early as 1976, when sportswriterLeonard Koppett proposed that RA would be a better measure of pitcher performance than ERA. [*Thorn and Palmer, p. 29.*] Subsequently, sabermetricianBill James wrote, "I think that the distinction between earned runs and unearned runs is silly and artificial, a distinction having no meaning except in the eyes of some guy up in the press box." [*James (1986), p. 483.*]In baseball, defense—that is, preventing the opponent from scoring runs—is the joint responsibility of the pitcher and the fielders. ERA attempts to adjust for some of the influence of the fielders on a pitcher's runs allowed by removing runs that are scored because of fielding errors—that is, unearned runs. However, removing unearned runs doesn't adequately adjust for the effects of defensive support, because it makes no adjustment for other important aspects of fielding, such as proficiency at turning

double play s, throwing out base stealers, and fielding range. Errors are the only aspect of fielding that ERA adjusts for, and are generally regarded as a small part of fielding in modern baseball. [*James (1987), p. 15. Wright and House, pp. 61–64.*]Another problem with ERA is the inconsistency with which

official scorer s call plays as errors. The rules give scorers considerable discretion regarding the plays that can be called as errors. ResearcherCraig R. Wright found large differences between teams in the rate at which their scorers called errors, and even found some evidence of home teambias —that is, calling errors to favor the statistics of players for the home team. [*Wright and House, pp. 52–59.*]While ERA doesn't charge the pitcher for the runs that result from errors, it may tend to over correct for the influence of fielding. Even though unearned runs would not have scored without an error, in most cases the pitcher also contributes to the scoring of the unearned run—either by allowing the opposing player to reach base via a walk or hit, or by allowing a subsequent batter a hit that advances and scores the runner. During the early days of baseball history, this over correction for fielding errors caused pitchers on bad teams to be overrated in terms of ERA. [

*Thorn and Palmer, pp. 28–29.*]Removing unearned runs in calculating ERA may be useful if they are unrelated to pitcher performance, but Wright concludes that fielding errors are somewhat dependent on a pitcher's style. Because errors occur most often on ground balls, pitchers with high

strikeout rates who give up fly balls are likely to give up fewer unearned runs than groundball control-type pitchers. For example,Ron Guidry —a flyballpower pitcher —andTommy John —a groundball control pitcher—were teammates on the Yankees from 1979 to 1982, supported by the same defense. During that period, 13.7% of John's runs allowed were unearned, compared to 9.8% of Guidry's. Wright concludes that this difference is attributable to their pitching styles, and thus, that unearned runs are partially attributable to the pitcher. [*Wright and House, pp. 60–61.*]**Adjusted RA+**Similar to

adjusted ERA+ , it is possible to adjust RA for the ballpark effects and compare it to the league average. The formula for this adjustment is::$mathrm\{RA+\}\; =\; 100\; cdot\; frac\{mathrm\{lgRA\{mathrm\{RA$

where

*"lgRA" = park-adjusted league run average

*"RA" = the pitcher's run average.Values of RA+ above 100 indicate better-than-average pitching performance. Unlike unadjusted RA, which must be higher than unadjusted ERA, a pitcher's adjusted RA+ can be either higher or lower than his adjusted ERA+.

**ee also***

Defense independent pitching statistics **Notes****References***cite book

last=Holway

first=John B.

year=2001

title=The Complete Book of Baseball's Negro Leagues: The Other Half of Baseball History

place=Fern Park, FL

publisher=Hastings House Publishers

isbn=0803820070

*cite book

last=James

first=Bill

authorlink=Bill James

title=The Bill James Historical Baseball Abstract

publisher=Villard Books

date=1986

location=New York

isbn=0394537130

*cite book

last=James

first=Bill

title=The Bill James Baseball Abstract 1987

publisher=Ballantine Books

date=1987

location=New York

isbn=0345341805

*cite book

last=Thorn

first=John

authorlink=John Thorn

coauthors=Pete Palmer

title=The Hidden Game of Baseball

publisher=Doubleday

date=1982

location=Garden City, NY

isbn=038518283X

*cite book

last=Wright

first=Craig R.

authorlink=Craig R. Wright

coauthors=Tom House

title=The Diamond Appraised

publisher=Simon & Schuster

date=1989

location=New York

isbn=0671677691

*Wikimedia Foundation.
2010.*

### Look at other dictionaries:

**Earned run average**— In baseball statistics, earned run average (ERA) is the mean of earned runs given up by a pitcher per nine innings pitched. The ERA tells the average number of runs a pitcher would surrender over the course of a full game had he been kept in for… … Wikipedia**Earned run average**— (ERA) ist eine Statistik im Baseball, welche angibt, wie viele gegnerische Runs (Punkte) ein Pitcher durchschnittlich in neun Innings zulässt. In die Berechnung gehen aber nicht alle Runs ein, die dieser Pitcher abgegeben hat, sondern nur die… … Deutsch Wikipedia**Earned Run Average**— (ERA) ist eine Statistik im Baseball, welche angibt, wie viele gegnerische Runs (Punkte) ein Pitcher durchschnittlich in neun Innings zulässt. In die Berechnung gehen aber nicht alle Runs ein, die dieser Pitcher abgegeben hat, sondern nur die… … Deutsch Wikipedia**earned run average**— ☆ earned run average n. Baseball the average number of earned runs allowed by a pitcher for each nine innings pitched … English World dictionary**Earned run average**— У этого термина существуют и другие значения, см. Era (значения). ERA (Earned run average) статистический показатель в бейсболе. Показывает уровень подачи питчера, то есть сколько ранов он пропускает в среднем за 9 иннингов. Чем ниже ERA, тем… … Википедия**earned run average**— Baseball. a measure of the effectiveness of a pitcher, obtained by dividing the number of earned runs scored against the pitcher by the number of innings pitched and multiplying the result by nine. A pitcher yielding three earned runs in nine… … Universalium**Long-Run Average Total Cost - LRATC**— A business metric that represents the average cost per unit of output over the long run, where all inputs are considered to be variable. Long term unit costs are almost always less than short term unit costs because in a long term time frame,… … Investment dictionary**earned run average**— earned′ run′ av erage n. spo a figure used to indicate the effectiveness of a baseball pitcher, obtained by calculating the average number of earned runs scored against the pitcher for every nine innings pitched Abbr.: ERA,era • Etymology:… … From formal English to slang**earned run average**— noun Date: 1947 the average number of earned runs per game scored against a pitcher in baseball determined by dividing the total of earned runs scored against him by the total number of innings pitched and multiplying by nine … New Collegiate Dictionary**Earned Run Average**— statistic that details the average number of runs scored against a pitcher per nine innings, ERA (Baseball) … English contemporary dictionary