SIERA
Skill-interactive ERA — newer ERA estimator that handles batted-ball mix better than FIP/xFIP.
What SIERA means
Accounts for the fact that ground-ball and high-K pitchers maintain lower BABIPs sustainably. Often the best single stat for predicting next-year ERA.
What counts as a good SIERA
Lower is better — roughly 4.4 is poor, 4 average, 3.6 good, and 3.2 or better elite.
Also written
siera_value
Source
FanGraphs