FIP Challenge Results Part I

Back at the All-Star break, I wrote a piece here asking Should Fantasy Owners Use FIP? I included a chart of all of the starting pitchers who had a difference of 0.50 or greater between their FIP and xFIP.

The article ended with a promise to follow up and see which metric did better in predicting pitchers ERA in the second half of the season. Here is the table from the original article, with one additional column, this one the pitcher ERA in the second half of the season.

Name HR/FB ERA FIP xFIP 2nd Half ERA
Greinke 3.1 2.12 1.97 3.13 2.21
Pineiro 3.5 3.20 2.99 3.77 3.83
Lincecum 3.9 2.33 2.01 2.78 2.67
Braden 4.6 3.12 3.40 4.62 7.40
Maholm 4.6 4.60 3.55 4.40 4.24
Wakefield 4.9 4.31 4.17 5.50 6.00
Kershaw 5.0 3.16 3.54 4.28 2.27
Lowe 5.5 4.39 3.74 4.38 5.05
Lee 5.7 3.47 3.27 4.13 2.92
Zambrano 5.8 3.53 3.79 4.55 4.14
Jurrjens 5.9 2.91 3.82 4.62 2.24
Niemann 6.2 3.73 4.47 5.49 4.15
Blackburn 6.2 3.06 3.97 4.90 5.47
E. Jackson 6.4 2.52 3.45 4.34 5.07
Pelfrey 6.5 4.47 4.01 4.51 5.67
Garland 7.4 4.53 4.60 5.13 3.42
F. Hernandez 7.4 2.53 2.95 3.47 2.43
Verlander 7.5 3.38 2.70 3.23 3.52
Bannister 7.5 3.66 3.93 4.46 6.63
Sabathia 7.5 3.86 3.73 4.29 3.53
Penny 7.55 4.71 4.19 4.97 5.08
Padilla 7.5 4.53 4.53 5.13 4.58
Washburn 8.0 2.96 3.88 4.46 5.23
Weaver 8.0 3.22 3.80 4.47 4.47
Blanton 15.3 4.44 4.74 4.00 3.62
Arroyo 15.3 5.38 5.68 4.99 2.24
Moyer 15.4 5.99 5.84 5.06 3.48
Cahill 16.1 4.67 5.83 5.18 4.59
Volstad 16.2 4.44 4.58 3.95 6.79
Porcello 17.8 4.14 5.03 4.41 3.92
Looper 17.9 4.94 5.71 4.65 5.54
Geer 18.5 5.79 5.87 4.61 7.07
Harden 18.6 5.47 5.17 3.91 2.55
R. Johnson 18.9 4.81 4.92 3.83 8.10

There are 34 pitchers in the above chart. On a raw scale, the xFIP metric did a better job of predicting 2nd half ERA, coming closer than FIP on 20 of our pitchers. Furthermore, xFIP did a better job of forecasting 14 of the 24 players with low HR/FB rates and did a better job forecasting six of the 10 players with high HR/FB rates.

In the original article, I projected the two systems would be fairly close to 50-50, so xFIP slightly exceeded my expectations (59-41). But what really surprised me was how few players’ 2nd half ERA fell in between the range of their first half FIP and xFIP. For example, Pineiro had a 2.99 FIP and a 3.77 xFIP and his second half ERA was 3.83, outside the range of the two systems. Only six of the 34 pitchers had 2nd half ERAs inside the range. Both FIP and xFIP correctly forecasted three of those pitchers.

Later today I will post a breakdown of all 34 pitchers in this survey.




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4 Responses to “FIP Challenge Results Part I”

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  1. drew says:

    shouldn’t you just look at whether the 2nd half hr/fb rate regressed closer to 11% expected by xfip or stayed closer to the 1st half hr/fb rate? the way you are doing it does not take into account whether things like k/bb improved or worsened. what should be measured is whether 2nd half FIP came closer to first half FIP or 1st half xFIP. or am i wrong? this is just me trying to make sense of the methodology.

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  2. drew says:

    like in the case with chris volstad. Can you really call it a win for either fip or xfip? he was a completely different pitcher the 2nd half, and the fact that his 2nd half era was closer to his first half FIP had nothing to do with any prediction that FIP made.

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  3. Brian Joura says:

    Hi Drew – thanks for reading and commenting.

    As fantasy players, we are looking to see if FIP of xFIP does a better job of predicting future ERA. In that sense, it really does not matter how the 2nd half ERA is produced by said pitcher.

    Of course, we could separate things further by grouping “predictions” that were correct by method versus correct by circumstance, but that seems counter-productive right now when we are dealing with such a small sample in the first place.

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  4. Jimbo says:

    Looking through the list, I think there might be a ‘theme’ among those where FIP did better. Seems to be more studs on that side of the ledger.

    I’ll definitely bookmark this article for next year. If I’m evaluating a trade for Sabathia or Lincecum this may not do the trick. If I’m trying to find out which flash-in-the-pan starter to dump or sell high…this picked up on the flukes fairly well in my opinion.

    Also makes me wonder if it could be used to predict the guys on their way to stud-dom. While Zambrano and Jurrjens were looking at similar situations around midseason, xFIP did better for Zambrano while Jurrjens went the other direction.

    I know this piece has a history of “follow ups” but I’m intrigued if this would be predictive of following seasons, not just 2nd halves. Might keep me from drafting Scott Kazmir on the fly “just because his ERA is always under 4.”

    Great article (and series for that matter)

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