Introducing SIERA: Part Two

Part 1 of this series marked the introduction of Skill-Interactive Earned Run Average, or SIERA, an ERA estimator that more accurately gauges the run-prevention skills of a pitcher relative to his controllable skills. Part 1 focused on the introductory aspects, similarly to going over a syllabus on the first day of class, but today we'll recap the steps that led to SIERA’s creation. One of the major reasons for SIERA’s existence is that prior estimators broke plenty of ground. In this respect, SIERA represents another evolutionary step in the process of removing the effects of defense on pitcher statistics that came into play when Henry Chadwick conjured up the earned run average metric over a century ago.

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