FIP
Fielding Independent Pitching (FIP) measures what a player’s ERA should have looked like over a given time period, assuming that performance on balls in play and timing were league average. Back in the early 2000s, research by Voros McCracken revealed that the amount of balls that fall in for hits against pitchers do not correlate well across seasons. In other words, pitchers have little control over balls in play. McCracken outlined a better way to assess a pitcher’s talent level by looking at results a pitcher can control: strikeouts, walks, hit by pitches, and homeruns.
A walk is not as harmful as a homerun and a strikeout has less impact than both. FIP accounts for these kinds of differences, presenting the results on the same scale as ERA. It has been shown to be more effective than ERA in terms of predicting future performance and has become a mainstay in sabermetric analysis.
For those curious, here’s the formula for FIP:
FIP = ((13*HR)+(3*(BB+HBP-IBB))-(2*K))/IP + constant
The constant is solely to bring FIP onto an ERA scale and is generally around 3.20. You can find historical FIP constant values in this spreadsheet, or you can derive the constant by taking league-average FIP and subtracting that from league-average ERA.
Context:
Please note that the following chart is meant as an estimate, and that league-average FIP varies on a year-by-year basis so that it is always the same as league-average ERA. To see the league-average FIP for every year from 1901 to the present, check the FanGraphs leaderboards.
| Rating | FIP |
|---|---|
| Excellent | 2.90 |
| Great | 3.25 |
| Above Average | 3.75 |
| Average | 4.00 |
| Below Average | 4.20 |
| Poor | 4.50 |
| Awful | 5.00 |
Things to Remember:
● Voros McCracken’s research was called Defense Independent Pitching Theory (DIPs Theory). It’s the building block of much of today’s pitching analysis. It can be a tricky concept to understand and counter-intuitive for most baseball fans. Refer to our sections on DIPs, BABIP, and Luck for more information.
● FIP does a better job of predicting the future than measuring the present, as there can be a lot of fluctuation in small samples. It is less effective in describing a pitcher’s single game performance and is more appropriate in a season’s worth of innings.
Links for Further Reading:
Intro to FIP – Big League Stew
Mike Silva Chronicles: FIP – The Book Blog
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I think that people should also read Tom Tippett’s excellent study on DIPS to see when DIPS does not worth for certain classes of pitchers: http://207.56.97.150/articles/ipavg2.htm
I could not find the original at Diamond Mind, but found this link via Google. They just had it on their website late last year but must have just dumped all the great articles he wrote while there. Too bad.
has anyone done a break-even analysis of walks versus home runs allowed, assuming that there is a direct trade-off? could be interesting.
How now, brown cow?
Home runs are random events.
Is a 180 foot fly ball a random event? Clearly, it is random: it may be caught or it may not. But how about a fly ball hit 380 feet? The non-random advocates would be forced to ask in what direction and in what park the fly ball was hit. In other words they can only certify its randomness by waiting until it lands. The same could be done for the 180 foot fly.
Baseball has non-uniform playing areas.
Not sure I’m clear on the constant in this formula…
In order to find the FIP of a given league, I need to know the FIP of the league, correct? To do this, am I simply solving the equation below for FIP:
FIP = ((13*HR)+(3*(BB+HBP-IBB))-(2*K))/IP + ERA – FIP
The formula in the calculator appears busted. It’s:
=(((13*B2)+(3*B3+B4-B5)-(B6))/B7)+3.2
…but I think it should be:
=(((13*B2)+(3*(B3+B4-B5))-(B6))/B7)+3.2
Actually it should be:
=(((13*B2)+(3*(B3+B4-B5))-(2*B6))/B7)+3.2
Hey Steve, is there any way we can look at what FIP mark corresponds to which percentile, as was the case before? I found that to be much more helpful than “average”, “above average” etc.
Aroldis Chapman currently sports a FIP of -0.64. Either (1) your fancy stat needs work, or (2) it doesn’t “measure(s) what a player’s ERA should have looked like over a given time period, assuming that performance on balls in play and timing were league average,” since ERA cannot be negative.
I haven’t run the numbers, but just looking at the equation leads me to believe FIPs can be negative, especially if you don’t give up home runs.
I don’t like this statistic. If it truly were fielding independent, it should not use hits allowed as one of the terms, since the defense directly influences that stat. Also, if this metric truly were predictive, the constant should not vary from one year to another with league ERA. If FIP were highly predictive, it should be used to predict league ERA, rather than depend on it.
A true fielding independent statistic would use an expected number of singles, doubles, triples & HR, based on number of each of the different types of balls in play (FB-IFFB, IFFB, LD & GB). Also, BB would be included. Then, a multiple linear regression or other sophisticated statistical tool such as Partial Least Squares or Principal Component Analysis, would be used to assign coefficients to each of those terms to predict how many runs would be expected.
Another intuitive flaw in the FIP is that it makes a distinction between BB and IBB. Putting a baserunner on intentionally or not does not have much influence on whether or not a run results from that baserunner. There is no way that BB & IBB should be weighted identically. I would find FIP at least slightly more acceptable if a lower coefficient were used for the IBB, with the argument that intentional walks are used to set up double plays and might on average have a lower probability of leading to a run scored than unintentional ones. But there is no way an IBB should completely cancel out a BB.
I like stats/numbers and I love baseball, but what’s wrong with ERA?
I know it’s supposed to be fielding independent, but this definitely does not add value to groundball pitchers who induce a high amount of double plays. An old time pitcher like Tommy John I imagine would have a horrible FIP as he did not strike out many and was great at inducing double play groundballs to make up for hits or walks. It also doesn’t add value to clutch pitchers who seem to pitch better when runners are on base. Nor would it give value to the Mitch Williams or Don Stanhouse pitchers who were famous for getting a save after loading up the bases but not allowing a run.
So why are homeruns multiplied by 13?? That is why these formulae are jokes! They are extremely subjective