[Drstrangelove]

Typically, I look at FIP and try to justify not using it as my final factor, although I don't make all my evaluations based upon just that one number. There are of course reasons why FIP won't give you exactly the right answer, especially if the sample size is small enough. Consistently low or high FIP over a 3 years is to me more or less enough to suggest the pitcher is much better or worse than average.

In the minors (and even on the majors), defense and luck can impact ERA+ and BABIP, a lot, imo, and I've made boo boos using those, although it's hard to ignore those when they are very good year after year. K/9 and K/BB can be misleading in isolation, but I do like those in the low minors as an indicator of potential, especially if they persist in the next level. However, a pitcher that grooves pitches and stays in the strike zone can have good K/9 and K/BB rates but not be ready for the next level.

Years ago, Bill James did a study that implied that low K rates (especially declining K rates) in the majors was an indicator of a pitcher who was potentially on the way down. I tend to view low K rates and low K/BB rates in the minors as an indicator of a sub-optimal talent.

So, there's no magic go to number, and sometimes, even the best scout can't figure it out.