Mood Music - Under Pressure by Queen
Much of the same principles that we talked about last time in "Using The Saber For Good: Batting" will still apply here. Using sabermetrics for more advanced analysis we will again attempt to isolate variables and associate them with certain outcomes, meaning, what are some things that are mostly under a pitcher's control that make them more or less effective?
As you may or may not recall from my last post, one of the fundamental tenants of saber analysis is in the randomness and unpredictable nature of balls put in play. In addition, a pitcher and his defense are inexorably linked when it comes to results based statistics like Earned Run Average (ERA). With an excellent defense behind a pitcher, tough plays get made, and the pitcher's ERA is boosted. The opposite is also true.
Without further ado, the formula for Fielding Independent Pitching (FIP):
So, as you can see, FIP only deals with statistical events that don't result in the ball being put in play, and therefore, cannot be affected by a fielder. Only walks, strike outs, and balls over the fence are considered, and as such, the pitcher is evaluated independently of his defense. The "+3.10" is a modifier to put FIP on the same scale as ERA, meaning, theoretically, a pitcher who had league average defense behind him would have the same ERA and FIP. Or, conversely, FIP is what a pitcher's ERA should be, with the assumption that there is a league average defense behind him.
I'm pretty sure there's going to be more after the jump, but I may have gotten lazy and just posted a picture of Jessica Alba again.
Oooh, sorry, it's just more words!
In my view, FIP is best used as a comparative tool. For example, is a pitcher's FIP considerably higher or lower than their ERA? If so, why? Usually, it is for one of two reasons. One, the defense behind the pitcher is especially great/terrible, or two, the contact in play not taken into account in FIP is particularly strong/weak.
In order to make this distinction, the easiest next step to take is by looking at contact ratios, and by assuming that strike outs > ground outs > fly outs. This is true for somewhat simple reasons: A strike out can never result in a hit, a ground ball can result in a hit, but not a home run, and a fly ball can result in a hit, or, ~10% of the time, a home run. And, of course, a pitcher's ability to avoid giving up any type of line drive is also very important.
For example, although Joba Chamberlain has a very respectable 2.79 FIP as he has done a good job of limiting walks and home runs, and has posted a solid K/9 of 9.64, 20% of the balls in play that he has given up have been line drives. So, while the defense behind him hasn't been terrific and he's been at the butt of some bad luck, Joba's ERA is considerably higher than his FIP because of the high number of line drives that he has given up so far this year.
So, in addition to overall metrics such as ERA and FIP, it's always a good idea to have a firm grasp of a pitcher's contact ratios: Strikeout percent, walk percent, ground ball percent, fly ball percent, line drive percent, and infield fly ball percent. And obviously, you want the strikeout percent, ground ball percent, and infield fly ball percent to be high, and the walk percent, fly ball percent, and line drive percent to be low.
Cheers! Leave me comments.