Diamond Digest
SIERA vs. xFIP vs. ERA: Why Batted Ball Data Makes SIERA the Sharpest Skill Test for Pitchers
Traditional ERA is a noisy, results-based statistic influenced by factors outside a pitcher's control. Advanced metrics like xFIP and SIERA offer better insights into a pitcher's true skill, with SIERA being the sharpest test due to its consideration of batted ball quality.
Marco Moretti·October 29, 2026
