Quote:
Originally Posted by Argonaut
NEW TESTING: IS FIP ARBITRARY?
In doing some unrelated testing on something else, I seem to have come to the conclusion that FIP may have some element of arbitrariness, calling into question how I view FIP in OOTP.
It started by my opening the Pandora's Box that is Catcher Defense. I was looking at Ivan Rodriguez on the 1997 Texas Rangers, and simulated a bunch of games against the Milwaukee Brewers with and without his elite defense.
It was actually kind of eerie, as Texas had a mirror image record:
Normal Pudge: 5093-4907
Crippled Pudge: 4907-5093
There is some more detail in the attached results. A great catcher increases K/9 and decreases BB/9, and also definitely contributes positively to ERA and FIP.
But wait, I thought FIP was fielding independent? Well, normally it's pretty close as shown in my Braves testing. But catchers are a different story, and if their pitch framing increases K's and reduces BB's, that should be a net benefit to FIP because BABIP isn't involved. It's cool that this is in OOTP, and it reinforces my attraction to defensive catchers.
And then we get to the puzzling part... the Rangers with the normal Pudge gave up more home runs? I tested this over and over to make sure what I saw was real. It's true, having a better Catcher Defense actually increases home runs against. This doesn't make any logical sense -- if there's more strikeouts and fewer walks, then innings should be shorter and there should be fewer opportunities for home runs.
The only reasoning I can think of for the additional home runs is that there is some arbitrary invisible hand at play to keep FIP within a range. More strikeouts + fewer walks = more home runs. The sanctity of FIP must be protected at all costs. Having a great catcher is still a net benefit, but it looks like there's an illogical drawback.
In all of my previous testing I've come away more appreciative of OOTP, but this is the first time I've been disappointed.
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First, thank you, again, for doing these tests and sharing your results.
Second, this has driven me crazy because we are missing information. Specifically, batters faced.
There are problems with trying to compare things on a per inning basis since Normal Pudge faces less batters per inning (less walks, less balls in play - thus less hits).
If we equalize per inning we get
Normal Pudge: 9560 HRs, 25,304 BBs, 53,588 K's
Altered Pudge: 9381 HRs, 27,186 BBs, 50,549 K's
*I try not to use the term "crippled"
So, Normal Pudge, still less BB's, More K's and, oddly, more HR's
But, the more home runs might, actually, make sense.
Normal Pudge gave up 179 more home runs and 1882 fewer walks, while striking out 3039 more.
But, all those fewer walks means batters had *more chances* to hit home runs.
If we look at the ratios of HRs to K's and BB's we get
Normal Pudge
HR/K = .1784
HR/BB = .3778
Altered Pudge
HR/K = .1856
HR/BB = .3451
It's what we'd expect.
Normal Pudge gives up less HR/K (because he gets more K's) but more HR/BB (because he gives up less BB's). The HR could actually be the same because the denominators are changing.
Now, there could be a problem with the engine not simulating PA's and just saying there's a higher chance of a BB or a lower chance of a K but the same chance of a HR with Altered Pudge. But not accounting for the fact that BB's and K's occur later in the PA than a HR.
We could estimate BF's if you had more data - like hits, hit by pitches, double plays, etc
Otherwise it's hard to say if something's wrong or if it's ok.
EDIT: Giving more thought, I didn't factor in the increased strikeouts to remove opportunities to hit home runs.
I think, the most likely explanation is what I said earlier. The game engine doesn't simulate full plate appearances, just results. So, a good defensive catcher leads to more K's and less BB's per PA, but the same amount of HRs per plate appearance (as opposed to home runs per balls in play - that makes no sense). I don't know. We need batter faced data.
EDIT: How much did you alter Pudge? The differences are between .1 and .2 runs per 9. Which is, about, 15 runs per year (for a catcher), or a win and a half.