In 2009, I did a column at the All-Star break to see if FIP or xFIP would be more helpful for fantasy players in making trades. This year I did the same thing. You can see the results below
Here is the table from the 2010 article, along with an additional column, the pitcher’s ERA in the second half of the season.
|Name||HR/FB||ERA||FIP||xFIP||2nd Half ERA|
There are 38 pitchers in the above chart. On a raw scale, the two systems were almost identical, with the FIP metric did a better job of predicting 2nd half ERA in 20 cases while xFIP did better 17 times. Furthermore, FIP did a better job of forecasting 14 of the 26 players with low HR/FB rates and both systems got five of the 11 pitchers (Davis being a wash) with high HR/FB rates.
In 2009, xFIP did better on a raw scale, as it did a better job predicting 20 of the 34 pitchers in the sample.
Similar to 2009, most of the pitchers fell outside the range predicted by FIP and xFIP. For example, Liriano’s FIP was 2.18 while his xFIP was 2.97. But he had a 3.31 second half ERA. Only seven of the 37 players listed above had a second half ERA between their first half FIP and xFIP. The two systems were close on this, too, with FIP being better on four of these seven pitchers. In 2009, 28 of the 34 pitchers had second half ERAs outside the range of their first half FIP and xFIP numbers.
Later today I will post a breakdown of all 38 pitchers in this survey.
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