Earned run average

Earned Run Average (ERA) is a statistic that measures a pitcher's effectiveness by estimating the average number of runs they allow per nine innings pitched. It reflects how well a pitcher prevents the opposing team from scoring, with a lower ERA indicating better performance. To calculate ERA, divide the total earned runs allowed by the pitcher by the number of innings pitched, then multiply by nine. This standardizes the statistic across different game lengths, offering a clear way to compare pitchers' pitching ability regardless of game situations.