Originally Posted by kxblue
I'll admit I am a casual fan (college basketball is my sport), but I have a question about stats.
Why are Arroyo's
important? Shouldn't his ERA (which is 2.06 after today's start), wins, and possibly WHIP be his sole measures of productivity as they are the only stats which really affect the outcome? After all, even if he is "lucky", why should his luck be counted against him?
Im not a big stat guy, so any explanation would be greatly appreciated. Thanks!
Here you go...
Pitchers, above all other players, depend on other players to produce things like Wins, ERA, WHIP, etc. In short, DIPS ERA is an isolation of only that which a pitcher can control regardless of his defense. It's an individual representation of how well a pitcher performed just like Runs Created is an individual representation of how well a hitter performed without regard to other players in the lineup.
If a pitcher has a much lower ERA than he does DIPS, then we can reasonably assume that the pitcher is either the beneficiary of a good deal of luck (BABIP randomness) or a good deal of fielder skill. If a pitcher has a higher ERA than DIPS ERA we can reasonably assume that said pitcher has been unlucky.
In 2005, the Cardinals (1.21 DIPS Rate) and the Astros (1.12 DIPS Rate) finished second and first in the NL respectively in Defensive Efficiency. DIPS rate is DIPS/ERA. Basically, you'll find that the better defensive teams will produce ERA numbers lower than they should given their collection of pitchers. There are exceptions, of course, but I haven't seen anything yet that would lead me to move DIPS to a lower rung on the individual contribution totem pole.
Wins? Not represenational of individual player skill. WHIP? The Hits portion of WHIP relies on BABIP randomness or defensive skill. ERA can vary wildly based on a number of factors (including bullpen quality and usage). None are as accurate in guaging a pitcher's actual performance as DIPS.
I'm not saying that DIPS or DIPS rate are the end-all-be-all in evaluating a pitcher's performance. But if we're talking about individual contribution, I'm going to look at that first because it tells us more about individual pitcher contribution than any other number.