FIP-based pitcher WAR uses the same park factor as rWAR (and it shouldn't).

hjrrockies · 09-09-2021, 06:17 PM

I have noticed that pitcher WAR seems to overrate my Rockies pitching staff all the time. I did a quick check using ERA+ and FIP-, and it appears that the same park factor is used for both, which is incorrect (see https://www.fangraphs.com/guts.aspx?...=0&season=2020). I'm guessing it's a very very slight oversight and an acceptable simplification for teams with more league average parks, but by using the same park factor, the adjustment to FIP is about 3x too large. This means pitchers in hitter's parks are overrated, and pitchers in pitcher's parks are underrated by the default pitching WAR.

However OOTP calculates park factors, it would probably be a simple adjustment to do a FIP only calculation as well, which would fix the pitching WAR calculation.

brotherblues · 09-09-2021, 06:29 PM

Very perceptive to catch that. A bit of a big deal I think, hopefully it gets addressed.

09-09-2021, 06:17 PM	#1
hjrrockies Minors (Single A) Join Date: Mar 2016 Posts: 78	FIP-based pitcher WAR uses the same park factor as rWAR (and it shouldn't). I have noticed that pitcher WAR seems to overrate my Rockies pitching staff all the time. I did a quick check using ERA+ and FIP-, and it appears that the same park factor is used for both, which is incorrect (see https://www.fangraphs.com/guts.aspx?...=0&season=2020). I'm guessing it's a very very slight oversight and an acceptable simplification for teams with more league average parks, but by using the same park factor, the adjustment to FIP is about 3x too large. This means pitchers in hitter's parks are overrated, and pitchers in pitcher's parks are underrated by the default pitching WAR. However OOTP calculates park factors, it would probably be a simple adjustment to do a FIP only calculation as well, which would fix the pitching WAR calculation.

09-09-2021, 06:29 PM	#2
brotherblues All Star Reserve Join Date: Nov 2020 Posts: 658	Very perceptive to catch that. A bit of a big deal I think, hopefully it gets addressed.