Feb
05

The stats we use: FIP

By

In previous editions of this series we’ve discussed UZR, a defensive statistic, and wOBA, an offensive one. Today we’ll move onto a pitching one. It won’t be the only pitching one we’ll discuss, just as wOBA won’t be the only offensive one. To the best of my abilities, here’s an explanation of Fielding Independent Pitching, or FIP.

Understanding DIPS

The roots of FIP extend back to 2001. In Baseball Prospectus’s annual book, Voros McCracken presented the case that pitchers have little to no control over what happens to balls put in play. The article itself is pretty easy to understand, so if you have a spare five minutes I suggest giving it a read. If not, I’ll provide the most important of McCracken’s findings.

He looked at how hits per balls in play fluctuated from year to year, and found that “pitchers who are the best at preventing hits on balls in play one year are often the worst at it in the next.” He then cites Greg Maddux, who had a poor rate of hits on balls in play in 1999, but was among the best in 1998. Pedro Martinez saw a similar trend, performing horribly in 1999 and excellently in 2000 on balls in play.

You can see for yourself. Here’s Pedro’s BABIP in 2000, .253, tops in the majors, and here’s his BABIP in 1999, third worst among qualifying starters. You can see Greg Maddux on that list as well, seventh worst among qualifying pitchers, while he finished sixth best in 1999. So if pitchers as prolific as Maddux and Martinez can go from among the best to among the worst in the span of one season, it should say something about the nature of a pitcher’s ability to control the outcome of balls put in play.

So what does a pitcher have control over? Tom Tango lists it in a spectrum, from 100 percent pitching to 100 percent fielding. On the 100 percent, or near-100 percent, pitching side: balks, pick-offs, HBP, K, BB, HR. Then there’s a gray area, where it’s partly the pitcher, partly the fielding, though tough to determine which. These outcomes include wild pitches, stolen bases, caught stealings, singles, doubles, triples, batting outs, and passed balls. On the 100 percent fielding side are running outs. The focus of FIP, then, is on the 100 percent pitching part of the spectrum.

Weighing homers, walks, and strikeouts

In our wOBA and UZR primers, we talked about linear run estimators. As a one-sentence recap, linear run estimators put a value on outcomes based on how they contribute to actual run scoring, based on years of historical data. In order to weigh home runs and walks as negative outcomes, and strikeouts as positives, we need to use the linear run estimators to create a ratio, so that we properly weigh the value of each. For those who don’t want to see formulas, skip to the next section. For those who want to see the actual numbers, here goes.

Why the 13:3:2 ratio? We need look no further than the linear run estimator. That’s the ratio of value between homers, walks, and strikeouts.

Scaling it to ERA

One attractive quality of many new statistics is that they scale to existing stats. That makes it easier for us to transition. Looking at raw wOBA, for instance, you might not be able to immediately recognize how good a player performed. But, because it’s scaled to OBP, we can look at the number with a sense of familiarity. It runs along the same scale, so if we know that a hitter with a .335 OBP is near league average, we can assume the same of a player with a .335 wOBA. Except, of course, that wOBA tells us more than OBP by itself.

To align to ERA, we simply add 3.2 to the FIP. That number can apparently fluctuate sometimes — I’ve seen Tango mention adding 3.1 as recently as 2008. But more recently he’s gone with the 3.2 number.

A note on xFIP

In browsing stats on sites like FanGraphs. you might notice a stat called xFIP. This takes the idea of pitcher control a bit further, positing that in addition to having little control over outcomes on balls in play, pitchers have little control over the rate at which their fly balls go for home runs. So, to normalize for this variance, xFIP looks at the number of outfield flies hit off the pitcher, and takes 11 percent of that, which is the league average percentage of fly balls hit for home runs. The equation remains the same.

The reason I like this is because pitcher see more consistency in their year-to-year strikeouts and walks than home runs. There’s still some year-to-year correlation with home runs, but just not as strong. Is that enough to warrant a further normalization? That’s for you to decide. Chances are, however, that we’ll stick to just FIP here when talking about the things pitchers do.

It’s not all about luck

A common misconception is that FIP treats outcomes on balls in play as luck. This is not true. As explained above, outcomes on balls in play represent a gray area, where we don’t know how to what degree the pitcher and fielders are responsible. FIP just strips those plays out of the equation. See the section below for further elaboration.

A good way to think about this is how Tango put it. What we want is ERA to equal FIP plus fielding dependent pitching, plus fielding, plus luck — therefore luck is just one component stripped out of FIP. There are two other components stripped out as well, both of which are probably more important than luck.

Remember: it tells us one thing

The more important thing to note about FIP is exactly what it tells us. It does not make claims about luck, per se. What it tells us is how a pitcher fared on events that were close to 100 percent in his control. Since we know that factors like luck and defense play into ERA, it’s valuable to know how a pitcher does in terms of events for which he’s solely responsible.

Later in the series we’ll get to tRA, which considers batted ball type, and SIERA, Baseball Prospectus’s take on the matter, which will be revealed in the upcoming Baseball Prospectus 2010.

Resources

The original DIPS article
Defensive Responsibility Spectrum
Tango elaborates on FIP

Categories : Pitching

104 Comments»

  1. JGS says:

    Does FIP take out inside the park home runs and treat them like any other non-home run hit?

  2. I’m a bit saddened that FanGraphs has removed the E-F line from their pages. Looking at a pitcher’s fluctuations year over year was a handy tool to weed out consistent trendlines from outlier seasons related to factors largely outside his control.

  3. pete says:

    Great stuff as always. One adjustment, though, that I would consider, would be using rate stats instead of totals. I would, for instance, use the average HR/FB rates of each park a pitcher pitched in, and then compare the aggregate rates of the pitcher, and use K rates and BB rates instead of totals, and then instead of weighing it to ERA, I’d just weigh it to ERA+ instead. Not to say that FIP or xFIP aren’t excellent stats, just that I think using rates could render them more accurate, which, of course, is never a bad thing.

    What I wonder is, since we have park adjustments already, when will we have hitter ability adjustments? I know these things “tend to even out”, but as you can see when comparing an AL East pitcher’s numbers with an NL-West or Central pitcher’s numbers, they don’t do so quite enough. I think it may be interesting to take xFIP (which I’m assuming will only continue to improve and grow more accurate, possibly in the way described above), and weigh it against the the average wRC+ of hitters faced. Or, to take it a step further, weigh it somehow against the level at which each hitter has been hitting over the past week or so, thus demonstrating a pitcher’s ability to neutralize hot hitters, and the like.

    Of course, once Hit/fx comes out, none of this will be necessary, since we can just aggregate the avg. velocities of balls leaving the bats off of of each pitcher for balls in play.

  4. A.D. says:

    I’m a big fan of FIP

  5. Rose says:

    Here’s a question…

    IYO…what’s better?

    Giving up Melky and some prospects for Javier Vasquez (@ $12M)

    Or not giving up Melky or any prospects and signing Erik Bedard for $1.5M with only incentives carrying it up to $7.75M.

    NOTE: Erik Bedard says he will be ready to pitch for the Mariners by May. Vasquez, is a horse, and will be ready from the get-go.

  6. Accent Shallow says:

    I don’t like xFIP at all, since it underrates pitchers who have a consistent ability to prevent home runs, such as, say, Mo and Sabathia.

    And while FIP is useful, it’s not perfect: http://www.hardballtimes.com/m.....-from-era/

  7. Steve H says:

    I like FIP as a tool to predict, I think it is often misused, or misrepresented. I think it’s better to use looking ahead, rather than looking behind. For example.

    Pitcher A: 3.25 ERA, 1.22 WHIP, 4.57 FIP
    Pitcher B: 4.65 ERA, 1.36 WHIP, 3.39 FIP

    I’d rather have pitcher A for that season, as he had a better season, even if he didn’t necessarily pitch better. If those 2 guys are free agents, and those are the only numbers I know, I’m signing Pitcher B in a heartbeat.

    • JGS says:

      This

      Pitcher A might have pitched better than pitcher B, he just didn’t have as good rates of BB/K/HR, hence the higher FIP (then again, he might be Dice-K, circa 2008)

    • That.

      FIP for pitchers is a bit like BABIP for hitters. It’s exceedingly useful to evaluate seasons that are outliers from a player’s norm to determine, say, whether a player had a down year not likely to be repeated or whether a player was over his head and will not sustain his sudden peak.

      A large gap between FIP and ERA is usually a red flag, one way or another.

  8. [...] Independent Pitching, or FIP, was borne of DIPS. Consistent with McCracken’s theory, FIP considers only a pitcher’s [...]

  9. [...] The 4.71 ERA is deceiving, because everything else suggests he’s been much better (4.10 FIP, 3.43 xFIP, 4.22 tRA). But hey, the Yankees have made a habit out of beating guys like this in the [...]

  10. [...] agree with the ERA though; a.J. had a ~4.25 FIP through those eight [...]

  11. [...] weird when you consider that the very next season the Yankees recorded both their worst ERA- and FIP- of all 43 teams surveyed here. I don’t know if they either blew the bullpen up following 1970 or [...]

  12. [...] Scott Proctor personifies the Joe Torre era bullpens. He had a modicum of success in 2006 (3.96 FIP) but was overworked to the extreme, appearing in 83 games and throwing 102.1 relief innings. [...]

  13. [...] which he struck out 9.4 men per nine, walked 2.2, and put up a pitcher triple slash 3.24 ERA/3.31 FIP/3.41 xFIP worth 6.0 fWAR, only to have Vazquez come apart at the seams in the second half of the [...]

  14. [...] 41, has enjoyed the four best seasons of his career — in terms of ERA and FIP — in the last four years. I don’t know how he did it, but the guy suddenly became a shutdown [...]

  15. [...] like a champ and came back a better pitcher, finishing the year with a shiny 3.70 ERA and 4.01 FIP in 165.1 IP. His peripheral stats improved as the season went on as [...]

  16. [...] where he served as Branden Pinder’s primary setup man. He pitched to a 2.40 ERA and a 3.03 FIP, striking out 41 batters (12.3 K/9 and 31.1 K%) and walking 15 (4.50 BB/9 and 11.4 BB%) with 52% [...]

  17. [...] easy answer here is that his ERA (3.70) was lower than his FIP (4.01) and he’s doomed to regress, but that’s not necessarily the case. The concern is Nova’s [...]

  18. [...] bullpen led the Orioles’ pitching staff to the worst collective ERA (4.92) and FIP (4.67) in the Majors last season. The offense also struggled, coming in at a below-league-average [...]

  19. [...] Thompson for assignment. The 27-year-old Australian-born right-hander pitched to a 3.00 ERA (3.27 FIP) in 54 IP for the Halos just last season, but they’d apparently seen enough after he allowed four [...]

  20. .zip file says:

    It’s not a finite elements analysis, but it is close…

  21. [...] their core bullpen arms are rested. Jose Valverde (3.59 FIP but the same number of walks as strikeouts) hasn’t appeared [...]

  22. [...] it hasn’t been lights-out it’s still been plenty effective (top seven NL in K/9, BB/9, ERA and FIP) — and to the surprise of everyone, have considerably outplayed expectations to the point of [...]

  23. [...] vs. LHP Jon LesterThere is no sugarcoating it, Lester has been pretty awful this year. His 4.18 FIP is fine but his 5.46 ERA tells a much different story. Last time out, he surrendered 11 runs and 14 [...]

  24. [...] 33, is having his worst season in five years (3.95 ERA and 3.40 FIP) but is still pretty darn good. He’s been much more homer prone (1.14 HR/9) than at any other [...]

  25. [...] not so young anymore at 26, has ridden his fastball and two curveballs to a 4.15 ERA and 4.70 FIP in 149.2 innings this year. He’s maddeningly homer prone, but outside of a disastrous April — [...]

  26. [...] as good as any closer in the game. During the 2009-2010 seasons, Wilson pitched to a 2.27 ERA (2.35 FIP) with 10.78 K/9 (28.7 K%), 3.24 BB/9 (8.6 BB%), and 47.3% grounders in 147 innings. MLBTR projects [...]

  27. [...] 25, was the club’s 17th round pick in the 2010 draft. He pitched to a 3.48 ERA (1.55 FIP) in 10.1 Triple-A innings this year, striking out ten and walking one. He managed a 4.05 ERA (3.32 [...]

  28. [...] 25, had a nice half-season (3.06 ERA and 3.85 FIP2) last year, but things haven t gone as well early in his sophomore campaign (4.65 ERA and 4.70 [...]

  29. [...] going any worse for CC Sabathia this year. The big left-hander is sitting on a yucky 4.73 ERA (4.20 FIP) in 160 innings across 24 starts, thanks in large part to a sudden Hughesian affinity for the long [...]

  30. [...] going any worse for CC Sabathia this year. The big left-hander is sitting on a yucky 4.73 ERA (4.20 FIP) in 160 innings across 24 starts, thanks in large part to a sudden Hughesian affinity for the long [...]

  31. [...] 62.1 innings since returning from surgery last August, Joba has a 4.33 ERA and 4.81 FIP. He had a 3.95 ERA and 3.14 FIP in 100.1 innings from 2010-2011 after moving back into the bullpen [...]

  32. [...] 31, had a typical Paul Maholm year for the Braves this year, with a 4.41 ERA (4.24 FIP) in 153 innings. He was just dreadful in the second half (5.73 ERA and 4.75 FIP) while battling an [...]

  33. [...] 29, had a 3.30 ERA and 3.43 FIP in 182.2 innings this season, but he was awful in the first half (4.56 ERA and 4.50 FIP) and great [...]

  34. [...] 38, pitched to a 3.31 ERA (3.56 FIP) in 201.1 innings this season. He faded badly down the stretch for the second straight year, as [...]

  35. [...] 36, had a 3.79 ERA (4.49 FIP) in 202 innings for the Reds this season. I have no interest in him for reasons I outlined in this [...]

  36. [...] 28, had a 4.93 ERA (5.64 FIP) in 42 innings this season and was especially dreadful in the second half (6.53 FIP). I’m [...]

  37. [...] runs in 1.1 innings. He spent the majority of the season with Triple-A Scranton (3.55 ERA and 3.22 FIP in 63.1 innings) after being claimed off waivers from the Athletics last winter. In 64.2 career big [...]

  38. [...] They bought him away from UNC with an $800k signing bonus. Mitchell pitched to a 5.12 ERA (3.47 FIP) in 126.2 innings for High-A Tampa …read [...]

  39. [...] who turns 39 on Friday, pitched to a 1.39 ERA and 2.26 FIP in 64.2 innings for the Rangers this season while going 43-for-46 in save chances. Following a [...]

  40. [...] 38, pitched to a 3.31 ERA and 3.56 FIP in 201.1 innings this past season, but he faded badly down the stretch for the second straight [...]

  41. [...] 38, had a 3.31 ERA (3.56 FIP) in 201.1 innings this past season, but he faded badly down the stretch for the second straight [...]

  42. [...] 29, had a 5.19 ERA (3.99 FIP) in 152.2 innings for the Twins in 2013, his first season following Tommy John surgery. At his best [...]

  43. [...] in six scoreless and walkless innings with New York in September. He was awesome (2.02 ERA and 1.88 FIP) in 53.1 innings at three minor league levels during the summer. The Yankees signed Daley two [...]

  44. [...] 35, moved into the bullpen full-time last season and had a 3.57 ERA (2.45 FIP) with awesome strikeout (9.43 K/9 and 25.4 K%) and walk (1.29 BB/9 and 3.5 BB%) rates in 63 innings [...]

  45. [...] the Tigers. He’ll join their revamped setup crew. Joba was awful in 2013 (4.93 ERA and 5.64 FIP in 42 innings) and finished his Yankees career with a 3.85 ERA (3.83 FIP) in 444.2 innings. There [...]

  46. […] right-hander Brett Marshall for assignment. The 23-year-old had a disappointing 5.13 ERA (4.62 FIP) in 138.2 innings for Triple-A Scranton this past season. He made his big league debut and allowed […]

  47. […] perfect one-year stopgap for the Yankees if Masahiro Tanaka is not posted? He has a 3.41 ERA (3.17 FIP) over the last two seasons, he misses bats (8.90 K/9 and 23.6 …read […]

  48. […] last week to clear a 40-man roster spot for Carlos Beltran. He had a disappointing 5.13 ERA (4.62 FIP) in 138.2 innings for Triple-A Scranton in 2013, though he did make his big league debut over the […]

  49. […] innings this past season. The Queens native was awesome in the minors, pitching to a 2.02 ERA (1.88 FIP) in 53.1 innings at three levels after returning …read […]

  50. […] 36, had a 3.79 ERA (4.49 FIP) in 202 innings this past season. His value lies in his durability (199+ innings in each of the […]

  51. […] pro career in 2012. He threw 64.1 innings across 14 starts that season, posting a 1.68 ERA (3.14 FIP) with …read […]

  52. […] not sure if he received an invitation to Spring Training. The 28-year-old had a 4.31 ERA (3.96 FIP) in 148.1 innings for the Athletics’ Triple-A affiliate last summer. He’s been at that […]

  53. […] 29, has a 5.90 ERA (3.58 FIP) in 29 career big league innings with the Red Sox, Blue Jays, and Angels. He managed a 3.71 ERA […]

  54. […] bullpen arm than his performance, he stayed with the team all season, pitching to a 3.39 ERA (4.32 FIP) in 77 […]

  55. […] in 55 games. Kelley was projected for $1.5M by Matt Swartz. The 29-year-old had a 4.39 ERA (3.63 FIP) with a 11.98 K/9 (31.3 K%) in 53.1 innings last […]

  56. […] 31, had a 3.24 ERA (3.93 FIP) in 211 innings for the Royals last year. He has been a horse, throwing at least 210 innings in […]

  57. […] 28, has been one of the top setup men in baseball these last three years (1.91 ERA and 2.31 FIP) …read […]

  58. […] in the Dominican Summer League for his first pro season in 2008. He managed a 4.15 ERA (3.25 FIP) in 39 innings while walking 18 and striking out 39. The club …read […]

  59. […] sign until the middle of April last year, remember. He did pitch better in 2013 (2.70 ERA and 3.65 FIP) than he did in 2012 (4.38 ERA and 3.83 …read […]

  60. […] 36, is probably the best free agent reliever still available. He had a 3.38 ERA (2.84 FIP) with a ton of strikeouts (11.07 K/9 and 28.3 K%) and ground balls (50.6%) in 66.2 innings last […]

  61. […] 36, is probably the best free agent reliever still available. He had a 3.38 ERA (2.84 FIP) with a ton of strikeouts (11.07 K/9 and 28.3 K%) and ground balls (50.6%) in 66.2 innings last […]

  62. […] said to only be due diligence. The 31-year-old pitched quite well last season (3.24 ERA and 3.93 FIP) but he’s very fly ball and homerun prone, making him …read […]

  63. […] is a local guy from New Jersey who went to Wagner College in Staten Island. He had a 4.91 ERA (4.68 FIP) in 44 innings for the Red Sox over the last two years while dealing with shoulder and thumb […]

  64. […] 24, had a 3.88 ERA (4.18 FIP) in 139 innings with Double-A Trenton last season, making one spot start with Triple-A Scranton. I […]

  65. […] He opted out of contract when he was advised he did not make the team. Aceves had a 4.86 ERA (6.35 FIP) in 37 innings for the Red Sox last season, spending most of the year in Triple-A. The Yankees will […]

  66. […] He opted out of contract when he was advised he did not make the team. Aceves had a 4.86 ERA (6.35 FIP) in 37 innings for the Red Sox last season, spending most of the year in Triple-A. The Yankees will […]

  67. […] He opted out of contract when he was advised he did not make the team. Aceves had a 4.86 ERA (6.35 FIP) in 37 innings for the Red Sox last season, spending most of the year in Triple-A. The Yankees will […]

  68. […] 25-man active roster all season, or be offered back to the Yankees. He had a 2.85 ERA (3.85 FIP) in 60 innings for Double-A Trenton last season, and this spring he allowed just one run in 9.2 […]

  69. […] 25-man active roster all season, or be offered back to the Yankees. He had a 2.85 ERA (3.85 FIP) in 60 innings for Double-A Trenton last season, and this spring he allowed just one run in 9.2 […]

  70. […] 29, has a 5.54 ERA (4.52 FIP) with a 8.2 K/9 (19.5 K%) in 37.1 career big league innings, all with the ChiSox from 2012-13. His […]

  71. […] 29, has a 5.54 ERA (4.52 FIP) with a 8.2 K/9 (19.5 K%) in 37.1 career big league innings, all with the ChiSox from 2012-13. His […]

  72. […] 32, had a 2.24 ERA (3.24 FIP) in 128.1 innings for the Pirates from 2011-12, his last two healthy seasons. There is no such […]

  73. […] 32, had a 2.24 ERA (3.24 FIP) in 128.1 innings for the Pirates from 2011-12, his last two healthy seasons. There is no such […]

  74. […] 21, had a 3.41 ERA (3.11 FIP) in 87 closely-monitored innings for Low-A Charleston last season. He missed most of 2012 with a […]

  75. […] The Yankees have not yet shown any interest in Scott Baker. The right-hander has a 2.81 ERA (4.76 FIP) with 26 strikeouts and ten walks in five starts and 32 Triple-A innings with the Rangers. He can […]

  76. […] so far. Maybe RHP Jaron Long, attack manager Kevin Long’s son? He’s got a 3.33 ERA (2.61 FIP) with a 20/5 K/BB in 24.1 innings for a River Dogs this year. He’ll substantially breeze adult […]

  77. […] 24, had a 2.39 ERA (1.72 FIP) in 26.1 innings across six starts and one relief appearance for Triple-A Scranton this year. He […]

  78. […] made a spot start for the Halos the other day (four runs in 6.1 innings) and has a 3.69 ERA (4.46 FIP) in 53.2 Triple-A innings this year. His best attribute is that he’s not Alfredo Aceves. I’m […]

  79. […] Tanaka was named the AL Pitcher of the Month for May, MLB announced. He had a 1.88 ERA (2.21 FIP) with a 42/6 K/BB in 43 innings across six starts last month, so it was very clearly deserved. […]

  80. […] Low-A Charleston to High-A Tampa, according to Josh Norris. The 20-year-old had a 2.92 ERA (2.90 FIP) in 61.2 innings for […]

  81. […] Chan-Ho Park, who had rejuvenated his career as a reliever, but he proved to be ineffective (5.12 FIP in 35.1 IP) for the Bombers and was DFA’d within few […]

  82. […] 28, has pitched to a 3.81 ERA (3.02 FIP) with an absurd 133/23 K/BB in 16 starts in 115.2 innings this season. He’ll earn $14M this year […]

  83. […] play any of those positions in the Futures Game. The 20-year-old Severino has a 2.99 ERA (~2.60 FIP) with 78 strikeouts and only 16 walks in 72.1 innings at mostly Tampa this season. Congrats to […]

  84. […] 26, had a 3.57 ERA (3.77 FIP) in 17.2 innings across a few short stints with the Yankees this season. He has a 2.76 ERA (2.84 […]

  85. […] 32, has a 2.85 ERA (3.11 FIP) in 41 Triple-A innings this season. He appeared in one game with the Yankees last September, […]

  86. […] to a minor league contract, according to Rich Dubroff. The 27-year-old had a 6.10 ERA (6.37 FIP) in 20.2 Triple-A innings with the Orioles before being released. Escalona has a 4.50 ERA (4.76 […]

  87. […] 37, has a 3.92 ERA (3.89 FIP) in 19 starts and 124 innings this year, though his strikeout (19.1%), walk (9.9%), and ground ball […]

  88. […] 30, has a 2.87 ERA (3.14 FIP) in 100.1 innings after missing the start of the season with a shoulder issue. He’s been […]

  89. […] 29, is 23-for-25 in save chances with a 2.76 ERA (1.73 FIP) in 32.2 innings during his first year as Mariano Rivera‘s replacement. Among pitchers to throw […]

  90. […] 29, was a popular trade topic around these parts a few years ago, when he had a 3.77 ERA (3.89 FIP) and averaged 194.2 innings a year from 2008-11. Then he tore his shoulder capsule in 2012 and has […]

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