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 of innings pitched and multiplying by nine.
A lower ERA means that the pitcher has allowed fewer earned runs. Therefore, a low ERA is a better score than a high ERA. In 21st century baseball, an ERA below 4.00 is considered good, and anything below 3.00 is great. An ERA below 2.00 is rare and signifies an exceptional pitcher.
ERA is the most commonly accepted statistical tool for evaluating pitchers. The formula for finding ERA is: 9 x earned runs / innings pitched. If a pitcher exits a game with runners on base, any earned runs scored by those runners will count against him.
In baseball, an earned run is any run for which the pitcher is held accountable (i.e., the run scored as a result of normal pitching, and not due to a fielding error or a passed ball).
An ERA between 2.00 and 3.00 is also considered excellent and is only achieved by the best pitchers in the league. An ERA between 3.00 and 4.00 is above-average. An ERA between 4.00 and 5.00 is average; the majority of pitchers have an ERA in this range.
Ed Walsh+Career Leaders & Records for Earned Run Average
|Rank||Player (yrs, age)||Earned Run Average|
|1.||Ed Walsh+ (14)||1.816|
|2.||Addie Joss+ (9)||1.887|
|3.||Jim Devlin (5)||1.896|
|4.||Jack Pfiester (8)||2.024|
3.98League Year-By-Year Pitching–Averages
Ed Walsh holds the MLB earned run average record with a 1.816.
Earned Run Average
| colspan=“3”>Earned Run Average All Time Leaders | ‘Top 1,000’ | | — | | Name | ERA (Raw ERA) | Rank | | Ed Walsh | 1.82 (1.816) | 1 | | Addie Joss | 1.89 (1.887) | 2 | | Jim Devlin | 1.89 (1.890) | 3 |
K/9 rate measures how many strikeouts a pitcher averages for every nine innings pitched. It is determined by dividing his strikeout total by his innings pitched total and multiplying the result by nine.
Website Innings per Game
Team innings per game is used to calculate Earned Run Averages (ERA).
The scoring symbol “K” was first used in the scoring of an actual game in 1868. One reason the letter “K” was used because “K” was the prominent letter of the word strike. Another reason the letter “K” is used is that it is made with 3 strokes of the pencil, symbolizing the 3 strikes for the strikeout.
There are two outs when a batter hits a ground ball to short. The shortstop boots it and the runner reaches first base. The next batter hits a home run. Those two runs are unearned because the error should have been the third out of the inning.
The purpose of the unearned run is to distinguish which runs a pitcher is at fault for allowing. Unearned runs do not count against a pitcher’s ERA.
Rube BresslerThe 10 worst ERAs of all time
Outfielder Ty Cobb, whose career ended in 1928, has the highest batting average in Major League Baseball (MLB) history. He batted . 366 over 24 seasons, mostly with the Detroit Tigers.
Most Seasons Played
WHIP reflects a pitcher’s propensity for allowing batters to reach base, therefore a lower WHIP indicates better performance. While earned run average (ERA) measures the runs a pitcher gives up, WHIP more directly measures a pitcher’s effectiveness against batters.
Usually, an average WHIP is around 1.30, while a good WHIP is under 1.10, and an elite WHIP is below 1. A WHIP over 1.50 is generally considered poor. Though they aren’t completely related, usually a pitcher with a good WHIP will have a good ERA as well.
On base percentage is typically judged about 60 points higher than batting average. A good average in baseball is . 300 in the MLB, so a good OBP in the MLB would be . 360.
A huge part of determining a pitcher’s true skill level, though, begins with the basic walk and strikeout rates. A great place to begin with pitchers is to look at their K-BB%. This is the strikeout percentage (rather than K/9) minus their walk percentage. The higher that number, the better.