FIP
Fielding-Independent Pitching (FIP) is an ERA estimator that uses the Tom Tango. Like other defense-independent ERA estimators that attempt to remove defensive support from ERA, FIP also removes other factors deemed outside a pitcher's control, such as sequencing and luck.
Comparison to DIPS[edit]
FIP is based on the same concepts as DIPS: a pitcher's effectiveness can be largely described by his HR allowed, K, and BB. This concept is based on Voros McCracken's observation that pitchers' BABIPs tended to show little persistence from year-to-year relative to walks, strikeouts, and home runs allowed.
FIP uses a simpler, less thorough formula than DIPS. Unlike DIPS, FIP does not adjust innings pitched based on adjustments to other stats to ensure that a pitcher's total batters faced remains the sum of all credited events. Because of this, FIP is also much simpler to calculate.
Formula[edit]
The formula for FIP is:
(13*HR + 3*BB - 2*K)/IP + C
where BB can include HBP and/or exclude IBB and C is a constant (usually around 3.2) that centers FIP around the same mean as ERA. C can be calculated for both leagues together in a given year or for each league separately.
The formula is derived from the average linear weights values for four types of events: HR, BB, K, and BIP. Each weight is presented relative to the average value of a BIP, so that the BIP term in the formula is 0. The formula is thus a simplified form of:
(13*HR + 3*BB - 2*K + 0*BIP)/IP + C
This fact makes it possible to calibrate the coefficients in FIP to different BIP values, such as in a very good or very poor defensive environment or in a park with an extreme BABIP park factor.
Mainstream Use[edit]
FIP is the basis of pitcher win values presented on FanGraphs.
2009 AL Cy Young Winner Zack Greinke cited FIP as a focus of his pitching strategy (1). Greinke's teammate Brian Bannister is a noted follower of sabermetrics and introduced Greinke to FIP.
