Monday, June 15, 2009
Using FIP to evaluate pitchers? I wouldn’t
Posted by Derek Carty at 2:01am |
| Is Derek Lowe the most overvalued pitcher in baseball this year? If you're looking at FIP he is. (Icon/SMI) |
What is FIP?
FIP is a statistic that attempts to estimate what a pitcher's ERA would be based on his peripheral statistics—or rather, the peripheral statistics originally suggested by Voros McCracken when he introduced DIPS Theory. This includes strikeouts, walks, hit-by-pitches, and home runs. While we know that strikeouts and walks are extremely important, eight years after Voros's work was originally published, we can definitively say that home runs aren't entirely under a pitcher's control.
Here's how things work: a pitcher can influence the rate of fly balls he gives up. By this logic, the more fly balls allowed, the more total balls will clear the fences for home runs (all else being equal). However, while a starting pitcher can control the rate of fly balls allowed, he cannot do a very good job of controlling the rate at which those fly balls become home runs (with very few exceptions).
To put it more simply, starting pitchers don't have any underlying ability to prevent home runs—the best they can do is prevent fly balls. If those fly balls are clearing the fence at too high a rate (or too low), we say that the pitcher has been unlucky (or lucky).
And therein lies the problem with FIP.
Pitchers undervalued by FIP
Here is a list of pitchers that have been undervalued by FIP so far in 2009. If you were to look at the FIP of these pitchers, you would believe that they have pitched worse than they actually have.
To explain the table below, we're seeing the pitcher's LIPS ERA (which also estimates ERA but normalizes HR/FB, in addition to some other things), his FIP, and the difference between the two. I've also included each pitcher's HR/FB rate so you can see just how much this stat influences FIP (for the worse). League average is around 11 percent, and you'll notice that just about every player on this list is well above that number.
+-------------+------------+----+----+-------+------+----------+------+----------+-------+ | LAST | FIRST | G | GS | IP | ERA | LIPS ERA | FIP | LIPS-FIP | HR/FB | +-------------+------------+----+----+-------+------+----------+------+----------+-------+ | Geer | Joshua B | 11 | 9 | 58.7 | 6.14 | 4.48 | 5.97 | -1.49 | 18% | | Guthrie | Jeremy | 13 | 13 | 73.3 | 5.52 | 4.39 | 5.78 | -1.39 | 17% | | Colon | Bartolo | 11 | 11 | 55.3 | 4.23 | 4.21 | 5.60 | -1.39 | 19% | | Harden | Rich | 9 | 9 | 49.7 | 4.53 | 3.18 | 4.47 | -1.29 | 23% | | Bush | David T | 13 | 12 | 74.7 | 4.58 | 4.34 | 5.52 | -1.18 | 17% | | Baker | Scott S | 11 | 11 | 67.7 | 5.59 | 3.76 | 4.93 | -1.17 | 17% | | Young | Chris | 13 | 13 | 73.7 | 4.76 | 4.16 | 5.13 | -0.97 | 11% | | Johnson | Randy | 13 | 13 | 70.0 | 4.89 | 3.61 | 4.55 | -0.94 | 22% | | Galarraga | Armando | 13 | 13 | 69.7 | 5.56 | 5.08 | 6.02 | -0.94 | 17% | | Blanton | Joe M | 12 | 12 | 71.3 | 5.17 | 3.97 | 4.86 | -0.89 | 19% | | Suppan | Jeff | 13 | 13 | 70.3 | 4.48 | 4.88 | 5.72 | -0.84 | 16% | | Moyer | Jamie | 12 | 12 | 66.3 | 6.11 | 4.97 | 5.81 | -0.84 | 16% | | Parra | Manny | 13 | 13 | 64.7 | 7.52 | 4.39 | 5.12 | -0.73 | 15% | | Davies | Kyle K | 13 | 13 | 77.0 | 5.14 | 4.67 | 5.34 | -0.67 | 14% | | Eaton | Adam | 8 | 8 | 41.0 | 8.56 | 5.29 | 5.96 | -0.67 | 16% | | Looper | Braden | 12 | 12 | 68.0 | 4.50 | 4.58 | 5.23 | -0.65 | 18% | | Oswalt | Roy | 14 | 14 | 82.3 | 4.37 | 3.96 | 4.56 | -0.60 | 15% | | Slowey | Kevin | 13 | 13 | 78.7 | 4.23 | 3.57 | 4.09 | -0.52 | 11% | | Sonnanstine | Andy | 13 | 13 | 70.3 | 6.65 | 4.97 | 5.48 | -0.51 | 16% | | Carmona | Fausto C | 12 | 12 | 60.7 | 7.42 | 5.58 | 6.08 | -0.50 | 18% | +-------------+------------+----+----+-------+------+----------+------+----------+-------+
While true for nearly all players to some extent, if you see analysis done on these players using FIP, take note that the conclusions should probably be much more positive.
Pitchers overvalued by FIP
Here is a list of pitchers that have been overvalued by FIP so far in 2009. If you were to look at the FIP of these pitchers, you would believe that they have pitched better than they actually have.
+-------------+------------+----+----+-------+------+----------+------+----------+-------+ | LAST | FIRST | G | GS | IP | ERA | LIPS ERA | FIP | LIPS-FIP | HR/FB | +-------------+------------+----+----+-------+------+----------+------+----------+-------+ | Lowe | Derek | 13 | 13 | 83.7 | 3.44 | 4.75 | 3.20 | 1.55 | 3% | | Billingsley | Chad R | 13 | 13 | 85.7 | 2.73 | 4.07 | 2.73 | 1.34 | 3% | | Stults | Eric W | 9 | 9 | 45.0 | 4.80 | 5.47 | 4.14 | 1.33 | 3% | | Jurrjens | Jair | 13 | 13 | 79.0 | 2.85 | 4.83 | 3.53 | 1.30 | 5% | | Garland | Jon | 13 | 13 | 76.0 | 5.45 | 6.42 | 5.13 | 1.29 | 9% | | Blackburn | Nick N | 13 | 13 | 84.3 | 3.31 | 5.40 | 4.22 | 1.18 | 7% | | Greinke | Zack Z | 13 | 13 | 94.3 | 1.72 | 3.01 | 1.92 | 1.09 | 2% | | Pelfrey | Mike A | 11 | 11 | 65.3 | 4.68 | 5.48 | 4.40 | 1.08 | 8% | | Lincecum | Tim | 13 | 13 | 88.0 | 2.66 | 3.24 | 2.22 | 1.02 | 4% | | Rodriguez | Wandy | 13 | 13 | 79.7 | 2.82 | 4.16 | 3.16 | 1.00 | 7% | | Hammel | Jason A | 12 | 9 | 54.0 | 4.33 | 4.94 | 3.99 | 0.95 | 11% | | Carpenter | Chris | 7 | 7 | 44.0 | 1.23 | 3.34 | 2.39 | 0.95 | 3% | | Jimenez | Ubaldo | 13 | 13 | 82.7 | 3.92 | 4.21 | 3.27 | 0.94 | 6% | | Meche | Gil | 13 | 13 | 75.3 | 3.70 | 4.00 | 3.08 | 0.92 | 3% | | Happ | J.A. | 16 | 4 | 45.3 | 2.98 | 5.34 | 4.42 | 0.92 | 9% | | Pineiro | Joel | 12 | 12 | 76.7 | 3.99 | 4.01 | 3.09 | 0.92 | 4% | | Verlander | Justin B | 13 | 13 | 86.3 | 3.02 | 3.26 | 2.36 | 0.90 | 6% | | Lee | Cliff | 13 | 13 | 88.0 | 3.17 | 4.03 | 3.15 | 0.88 | 6% | | Miller | Andrew M | 10 | 8 | 46.0 | 4.30 | 4.45 | 3.62 | 0.83 | 5% | | Johnson | Josh | 13 | 13 | 89.0 | 2.73 | 3.55 | 2.72 | 0.83 | 6% | | Washburn | Jarrod | 12 | 12 | 76.3 | 3.30 | 4.53 | 3.71 | 0.82 | 7% | | Padilla | Vicente | 11 | 11 | 65.3 | 4.82 | 5.70 | 4.89 | 0.81 | 8% | | Wakefield | Tim | 12 | 12 | 76.0 | 4.50 | 5.50 | 4.75 | 0.75 | 6% | +-------------+------------+----+----+-------+------+----------+------+----------+-------+
While true for nearly all players to some extent, if you see analysis done on these players using FIP, take note that the conclusions should probably be much more negative.
Evaluating on your own
If you're looking for an alternative to FIP for evaluating players on your own, you have a few options. LIPS ERA is my favorite, and it's now available in Heater Magazine. You could also simply go with xFIP, which appears on every THT player page and is sortable on the leaders pages. Other free options include stats like tRA and QERA.
Concluding thoughts
Hopefully this cleared some things up for some of you, as I know I've gotten a few questions about FIP this season. For those of you who were already aware of its shortcomings, well, hopefully you at least enjoyed chewing on the leaderboards presented. As always, if you have any questions, feel free to e-mail me or comment.
Derek Carty, 23, has also been published by NBC's Rotoworld, Sports Illustrated, FOX Sports, and USA Today. This season, he'll be contributing to FanDuel and will be linking to all of his work at DerekCarty.com. In his three years competing in expert leagues, he has won 2 titles with 4 top three finishes, including a LABR NL title in 2009, making him the youngest person to ever win a major expert league title. Derek is a proud graduate of the MLB Scouting Bureau's Scout Development Program and is a firm believer in the importance of combining stats and scouting. He welcomes questions via e-mail, Facebook, or Twitter.
Good stuff, Derek. I like the philosophy behind LIPS ERA and Baseball HQ’s xERA best.