Earned Run Avg (ERA) Records and Details
What is Earned Run Avg (ERA) ?
Earned run average (ERA) is a metric that shows how many earned runs on average, a pitcher or team's pitcher, gives up over the course of nine innings. It is calculated by dividing earned runs by innings pitched then multiplying the result by 9. Generally, for Earned Run Avg (ERA), lower is better. (Source)
What is a good Earned Run Avg (ERA)?
What does good Earned Run Avg (ERA) mean? "Good" baseball stats can be very subjective and mean different things to different people. I have attempted to quantify good and bad by taking season and career stats for MLB pitchers with a minimum number of pitched outs. In this case 100 for career and 50 for a season. To find good and bad within this cohort of players I calculated the first and third quartiles, anything between these quartiles I consider average. This makes up the middle 50% of players. In an example where higher is better for a stat, below the first quartile (bottom 25% of players) would be bad and above the 3rd quartile (top 25% of players) would be good. For stats where lower is better, flip around good and bad.
Career, Season, and Season Average Earned Run Avg (ERA) Records
For my hot take on Earned Run Avg (ERA) records most of the same rules apply from the first section. To be considered for my prestigious lists the player must meet a certain threshold of pitched outs. Since this is a Pitching stat to be considered for the career list the player must have over 100 pitched outs, for a season consideration the player must have had 75 pitched outs. Additionally, the player's final game must have been after 1899.