Baseball Glossary › Fielding Independent Pitching
Fielding Independent Pitching (FIP)
Fielding Independent Pitching (FIP) estimates a pitcher's run prevention using only the outcomes he controls most: strikeouts, walks, hit-by-pitches and home runs. Balls in play are left out because defense and luck shape them. A constant puts FIP on the same scale as ERA, so it reads like an ERA.
Formula
Worked example (illustrative numbers, constant assumed at 3.10): 180 innings, 20 home runs, 50 walks, 5 hit batters, 180 strikeouts.
13 x 20 = 260; 3 x (50 + 5) = 165; 2 x 180 = 360
(260 + 165 - 360) / 180 = 65 / 180 = 0.36
FIP = 0.36 + 3.10 = 3.46
What to Know
The FIP constant exists only to put FIP on an ERA scale. FanGraphs says it is generally around 3.10, and it is set each season so that league-average FIP equals league-average ERA. That is the direct answer to what league-average FIP is: whatever league ERA is that year.
FIP vs ERA: ERA charges a pitcher for every earned run, including those caused by poor defense or bloop hits. FIP ignores balls in play, which is why a pitcher with a high BABIP against often has a FIP well below his ERA. FanGraphs' rough guide, based on the 2016 run environment, puts about 4.20 at average, 3.80 above average, 3.50 great and 3.20 excellent.
FIP rests on the same ingredients as strikeout rate and K/BB. FanGraphs also uses FIP as the pitching basis of its version of WAR.
Frequently Asked Questions
What is FIP in baseball?
FIP stands for Fielding Independent Pitching. It estimates what a pitcher's ERA should be based only on strikeouts, walks, hit batters and home runs, leaving out balls in play that depend on defense and luck.
How is FIP calculated?
Multiply home runs by 13, add 3 times walks plus hit batters, subtract 2 times strikeouts, divide by innings pitched, then add the FIP constant, which FanGraphs says is generally around 3.10.
What is league average FIP?
League-average FIP equals league-average ERA for that season, because the FIP constant is set to make them match. FanGraphs' rule-of-thumb scale, based on the 2016 run environment, uses about 4.20 as average.
What is a good FIP?
FanGraphs' rough guide, based on the 2016 run environment, puts 3.20 at excellent, 3.50 great, 3.80 above average and 4.20 average. Compare against league ERA in the same season, since scoring levels change.
Why is FIP different from ERA?
ERA counts every earned run, so it is affected by the defense behind the pitcher and by luck on balls in play. FIP strips those out. When a pitcher's FIP is much lower than his ERA, poor defense or bad luck may be inflating his ERA.
Is FIP better than ERA?
They answer different questions. ERA records what happened. FIP isolates the pitcher's own contribution and often predicts future ERA better than past ERA does, so analysts usually look at both.
Related Terms
Sources
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