I pre-apologize to those who have heard this before.
The main reason pitching related stress is of interest to me, has to do with better understanding pitching injuries. It started some years back when Pitcher Abuse Points were dreamed up over at Baseball Prospectus. http://www.baseballprospectus.com/article.php?articleid=1477 There were a lot of folks, mostly MLB owners, who were getting sick and tire of signing some HS or college phenom to a nice fat contract, only to lose them entirely, or for at least a couple years to some kind of arm injury. Well, you can judge the article for yourself, but it at least quantified something for the 1st time, and may well have been the cause of what everyone now calls the Pitch Count Era.
For a few years, PAP was metric of choice for such things, but like all metrics, people found ways to improve on it as more knowledge became available. So, out came PAP Cubed. http://www.baseballprospectus.com/article.php?articleid=1480
PAP ^3 is really nothing more than a refinement of the algorithm, by subtracting 100 from the number of pitches, then cubing the result. It just acknowledged the fact that once a pitcher got fatigues, the more “dangerous” it was for him to continue.
Since that was done in 2002, there has been a lot more study about pitchers, and one thing that’s definitely come into play, is the amount of rest between appearances. Unfortunately, so far that hasn’t been quantified into PAP, at least that I know of. But even more than that, here lately “stress” has been acknowledged as a factor contributing to fatigue as well, and that hasn’t been factored into the PAP equation either.
I’ve been staying pretty much on the simple route here. To me there are all kinds of levels of stress, but trying to get too nit picky something is just wasted effort. But, something simple like, let’s give one factor to pitches thrown with no runners on, least stressful, to a higher factor for pitches thrown with runners on, more stressful.
Although it would never be possible to predict exactly if or when a pitcher was going to suffer an injury, at least with the best information, it would be possible to make the red light and sirens go off.
And that’s where the metric on page 30 of http://www.infosports.com/scorekeeper/images/cpitching.pdf is headed, or at least that’s where I hope its headed. It allows me to determine the number of pitches PAP is based on, and as soon as I can get some kind of factor for “stress”, I’ll be ble to factor in the different pitches WRO or WNRO.
BTW, its my understanding that pitcher who get drafted out of HS are much less likely to suffer a pitching injury within 2 years of signing a contract than college pitchers. The reason I was given is, the high quality HS player who gets drafted is pretty much treated with kid gloves for those 2 years, while the same kid in college would very likely be worked like a plow horse, with less quality of instruction or medical attention.
Anyhoo, that’s why I wuz innerested.