Earned Run Average
Stat of the Week
by Peter Liubicich
Earned Run Average
This post was written by Peter Liubicich on April 16, 2012
Posted Under: Stat of the Week

We are only a week and a half into the 2012 season so it is still too early to look at players’ statistics and assume that is how they will perform for the rest of the season.  Some of the amazing feats we’ve seen so far, however, include Matt Kemp who is making his statement for why he should have been MVP last year with a Batting Average of .487, .523 On-Base Percentage, 1.026 Slugging Percentage, an OPS of 1.548, and six Home Runs in 10 games.  Another amazing early season performance has been Washington Nationals phenom Stephen Strasburg, who besides having the biggest burger in MLB associated with his name, has also posted an Earned Run Average (ERA) of 0.69 over two starts.  ERA is a baseline statistic next to a pitcher’s Win-Loss record that everyone sees while looking at the probable starters for the day in the sports section of the newspaper or when they flash a pitcher’s stats during a TV broadcast.

ERA is one of the more basic weighted statistics as the formula is:

Since pitchers don’t always pitch complete games, ERA projects how many Earned Runs a pitcher would give up if they pitched 9 full innings.  ERA serves as an explanatory statistic for a pitcher’s effectiveness and durability in a season as by giving up less Earned Runs and pitching more innings leads to a lower ERA.  What ERA does not factor in, however, is poor defensive play behind a pitcher, or luck, which makes statistics such as Fielding Independent Pitching (FIP) better indicators of a pitcher’s effectiveness.

Historically, the lowest ERA posted in a single season by a starting pitcher is Tim Keefe with an ERA of 0.86 in 1880.  There is obviously a huge difference in terms of offense compared to the game today as on the list of the top 100 lowest ERAs in a single season by a starting pitcher, there have only been nine pitchers on the list since John F. Kennedy held office.  That list includes Bob Gibson in 1968 (1.12), Dwight Gooden in 1985 (1.53), Greg Maddux in 1994 (a strike-shortened season but Maddux still started 25 games and posted an ERA of 1.56), Luis Tiant in 1968 (1.60), Maddux again in 1995 (1.63), Dean Chance in 1964 (1.65), Nolan Ryan in 1981 (Ryan only started 21 games and threw 149 innings while posting an ERA of 1.69), and Sandy Koufax in 1964 and 1966 (1.74 and 1.73).  In terms of relievers, my favorite statistic involving ERA is Mariano Rivera’s career postseason ERA of 0.70, giving up just eleven Earned Runs in 141 Innings Pitched justifying his title as the Greatest of All Time for closers.

If you are interested in reading up on pitching dominance, here is an interesting article from ESPN last year detailing the Year of the Pitcher, 1968.  Come back on Thursday where I’ll delve further into the success of Stephen Strasburg in terms of ERA (when he is healthy), NL Cy Young winner Clayton Kershaw and Mariners ace Felix Hernandez.

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Reader Comments


  1. WHIP  on May 7th, 2012 @ 2:01 pm
  2. Walks — Player Analysis  on June 7th, 2012 @ 6:36 pm

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