What is FIP in Baseball?

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FIP, or Fielding Independent Pitching, is a statistic used in baseball to measure a pitcher’s effectiveness. Unlike ERA (Earned Run Average), FIP focuses on analyzing a pitcher’s performance outside of plays they cannot control. FIP takes into account strikeouts, unintentional walks, hit-by-pitches, and home runs, which are all factors within a pitcher’s ability to control, while factors such as flyouts and ground outs are not.

The formula for FIP, according to Baseball Reference, is (13HR + 3BB – 2*K)/IP + C, where HR represents home runs, BB represents walks, HBP represents hit-by-pitches, K represents strikeouts, and C represents the league constant. A good FIP score is typically in the 2s and lower 3s, similar to a good ERA score.

xFIP, or Expected Fielding Independent Pitching, is a variation of FIP that uses projected home run rates instead of actual home runs allowed to remove the luck associated with home runs from the equation, providing a more accurate prediction of a pitcher’s skill.

FIP differs from ERA and WHIP, as it focuses solely on a pitcher’s performance in protecting the bases, without factoring in circumstances that involve the other players’ participation in defending the bases. While FIP can provide a more accurate analysis of a pitcher’s abilities, it has flaws, such as being more suited for long-term analysis and being affected by factors such as the park a pitcher is playing in.

FIP was developed by Tom M. Tango and derived from the research of Voros McCracken. It is best used for analyzing a pitcher’s performance over an entire season, while statistics such as WHIP and ERA are more suitable for analyzing a pitcher’s performance over a few games. Overall, FIP allows a pitcher’s skills to stand alone, providing a more accurate picture of how the pitcher plays their position.