Thursday, August 01, 2013
Standard wOBA
OBP's formula doesn't change, regardless as to the relative value of the HR to the ngle, given the circumstances.
SLG's formula doesn't change, regardless as to the relative value of the HR to the single, given the circumstances.
The core of FIP doesn't change, even though it should. (It does have a fudge factor though.)
It seems to me that what helps these metrics is that they have a standard formula, and then analysts can tweak them to suit their purposes.
wOBA should be like that, have a standard formula. This is what I use:
Version 1 - Basic
numerator:
0.7: UBB+HB
0.9: 1B+ROE
1.3: 2B+3B
2.0: HR
denominator: ?PA - IBB - SH
Version 2 - Speed
numerator:
0.7: UBB+HB
0.9: 1B+ROE
1.25: 2B
1.60: 3B
2.0: HR
0.25: SB
-0.5: CS
denominator: ?PA - IBB - SH
If you don't have ROE handy, then ignore it. If you don't have walks split between UBB and IBB, then ignore the distinction. If you don't have SH, ignore that too. Same deal with steals.
So, that's what I'd like to see for non-Fangraphs sites. It's nice and simple.
The key point by the way is that you start with "1" for any positive event (i.e., the numerator of OBP), but adjust it up and down relative to the event. The overall average of these events will come out to "1", which is why it is called a "weighted" on base average. Both metrics (unofficial OBP and wOBA) share the same denominator.