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Wednesday, August 10, 2011
Basic wOBA?
As we’ve found out, FIP does not work at all run environments. The coefficients work for pitchers if they give up around league average runs. But the further away you are, then the more the coefficients need to change. If you wanted to do FIP the right way, that’s what you’d have to do. However, the appeal to FIP is that we get a quick look by using nice constant coefficients. If we had to figure out the new weights for each pitcher and each year, it would lose a great deal of appeal.
wOBA was never intended for mainstream use. It was conceived for The Book. And wOBA, done right, would be FIP done right: proper coefficients for each run environment. So, some years, the coefficient for the HR is 1.90 and others it’s 2.10 and so on.
But, the appeal to FIP is the non-changing coefficients, and we calibrate by using a constant (we’d add +3.20 or +3.00, etc, as the case warrants it).
Indeed, when I use wOBA as a quick calculation, I use this:
wOBA
= 0.7 * (BB + HB)
+ 0.9 * (1B + ROE)
+ 1.3 * (2B + 3B)
+ 2.0 * (HR)
If I need to align it to some league level, or if I want to make it cross-era useful, I’ll just apply some overall constant to line them up. That is, I use the same principle behind FIP: keep the coefficients, and apply an overall fudge factor.
My questions:
1. Do you prefer to see a non-changing wOBA formula, like FIP?
2. If so, do you prefer to align to that particular year, or do you want the league average to always be 0.330?