The Gold Standard of Pitching
Since 1912, the Earned Run Average (ERA) has been the definitive metric used to evaluate the effectiveness of a baseball pitcher. It answers one simple question: If this pitcher were left on the mound for an entire 9-inning game, how many runs would they give up?
Isolating the Pitcher's Performance
The brilliance of the ERA metric is the word "Earned."
Baseball recognizes that pitchers are not responsible for the fielding mistakes of their teammates. If a shortstop drops a perfectly easy pop-fly, and the runner eventually scores, that run is classified as "Unearned." Unearned runs do not count against the pitcher's ERA.
The Formula
To calculate the average, you multiply the Earned Runs by 9 (for a 9-inning game) and divide by the total number of innings pitched.
ERA = (Earned Runs * 9) / Innings Pitched
What is a "Good" ERA?
- Under 3.00: Elite, 'Ace' level starting pitching. These pitchers are usually in contention for the Cy Young Award.
- 3.50 to 4.00: A solid, reliable middle-of-the-rotation starter.
- Over 5.00: The pitcher is struggling severely and is likely at risk of losing their spot on the team.