As we all know, Fangraphs is a great site... They continuously pump out great content, and they damn sure know who to hire (I'm looking at you, Erik...)
One beef that I do have with them, however, is the fact that they don't have FIP splits, something that should be easy given their resources. This would provide even better background on a pitcher's true abilities by quantifying how they fare in certain situations.
I decided to do it on my own. Results after the jump
First, the methodology. According to THT, FIP is calculated (HR*13+(BB+HBP-IBB)*3-K*2)/IP, plus a league-specific factor (I used 3.20). Using baseball-reference, it was doable, albeit tedious, to find splits of each of these stats. The only trick is with IP... Obviously, they don't keep these statistics for LHP and RHP, etc., so what I did (at vivaelpujols' suggestion) was take (PA-BB-H-CS+DP-SF)/3. It wasn't perfect, but the IP were, like he said, within a couple of innings of the actual result. There wasn't much change from the original, erroneous calculation, at most a tenth of a point in ERA.
Here's what I found:
|Pitcher||Total||vs RHB||vs LHB||Home||Away|
*both Boston and St. Louis stats
One thing you'll notice is that the FIPs I got are different from fangraphs'. I suspect that it's because their league-specific factor isn't actually 3.20, but it's close enough.
So what does this mean? What does this tell us that other measures can't? Well, most of it we can get by watching the games. Trever Miller is awesome against LHB. Todd Wellemeyer is not. Ryan Franklin, who sucks, likes to pitch at home. Take from this what you will... it takes awhile to get all the information from BR, but apart from that, it wasn't hard to do.