K%: .77
BB%: .69
HR%: .28 (that’s not HR/FB, by the way – thats HR/TBF)
LD%: -.03 (like I said, pretty random)
GB%: .79
FB%: .73

Excellent, thanks for both those answers (the cite and the correlations).

A groundball will be turned into an out approximately 61% of the time, while a flyball will be turned into an out approximately 78% of the time. The grounder actually has more of a chance of finding a hole than a flyball does of dropping in.

The issue, though, is that when a groundball “finds a hole”, its a single, which isn’t a huge deal. When a flyball “drops in”, its a double, a triple, or a home run, which is a huge deal. The run value of a home run is 1.45 runs, while the run value of a single is just .45 runs.

So, the groundball pitcher will give up more hits, but less impactful hits, than the flyball pitcher.

That’s why I said “all things being equal, the groundball pitcher is better.” But again, things are almost never equal, so I’m certainly not advocating acquiring a staff full of groundball pitchers and ignoring all the other skills.

Anyway, as I said it is very late and I’ve already stayed up later then I wanted. I will review the rest of the post and hopefully arise at a clearer understanding.

I may be going out on a limb here, but I don’t think there’s a snowball’s chance in Hell Grover comes back next year. Bavasi will find a way to get rid of him. I just think that Bill’s had it with Grover’s mindset. I realize Bavasi said that he just provides the pieces and says nothing to the manager about using them, but when the manager never uses them at all, and you’re spending good money to have them there, it can get irritating. Hargrove’s misuse of his bench, bullpen, and other factors warrant his dismisal alone, but “wasting” the company’s money? Bavasi can put that through the FO.

Bingo. It’s still good information to have, because if you’re looking at a guy with a low walk rate, a high strikeout rate, a low home run rate, and a high ERA, you’ll wonder what the heck is going on. That theoretical pitcher almost certainly has a ridiculously low LOB%.

Absolutely we should take it seriously. It has a significant impact on run scoring. If you wanted to explain to someone why Felix was struggling, his 66.9% LOB% this year would be a great place to start. When he’s put guys on, they’ve scored. That’s been a problem.

Is it predictive? Kind of, but not really. Not any more so than establishing an expected LOB% based on a pitcher’s other component rates, anyways.

How much of that variance is due to the low IP numbers for relievers? It seems dangerous to divide by small numbers and make rate projections when you are dealing with small denominators.

That’s a huge chunk of it, no doubt. Reporters love to quote things like Julio Mateo’s 2.42 ERA in his last 21 outings, but that covers a whopping 22 innings. If he had given up 10 runs instead of 6 during that time, his ERA would be nearly 4.00. Using rate stats in small samples can make the differences look much larger than they really are.

Good discussion and explanation, the one thing that’s missing is the data to support the statements that certain components (GB%) are relatively repeatable by a pitcher whereas others (HR/FB%) are not. E.g. what are the correlations of those components from year to year?

Most of this work has been done by the guys at The Hardball Times. David Gassko and J.C. Bradbury have an article in the 2006 Annual dealing with these issues. You really should buy the book, but here are some year to year correlations for you:

K%: .77
BB%: .69
HR%: .28 (that’s not HR/FB, by the way – thats HR/TBF)
LD%: -.03 (like I said, pretty random)
GB%: .79
FB%: .73

The THT article has a ton of other great stuff, too, including more accurate baselines than I included above and correlations on a bunch of other statistics, plus the analysis that goes along with things like HR/FB rates and outs on balls in play.

if I’m understanding correctly HR% is not as useful a measure as FB% … and HR/FB% is largely a matter of luck.

Right – once you account for FB%, home run rate is almost totally random – .08 year to year correlation.

This kind of analysis is easy to lose at the bottom of 200+ comments in a game thread. I wonder if you’d consider breaking it out into its own post. I expect you’d get a nice discussion going that would educate a lot of readers.

Not a bad idea.