[Drstrangelove]

I by no means want to throw a damper on your work (a well done study, I might add), but if catching ability reflects the ability to catch third strike foul tips, that could wipe enough of the variance to make it less obvious. This is not to say your observations lack merit, nor to suggest that my suggestion holds any water, but you asked for thoughts and that sprang to mind. The ideal study would have pitch location and demonstrate that the probability of a strike being called rises in certain pitch locations depending on the catcher's catching skill.

Of course, a simpler answer could be that it's a small sample size, but you already know that's a weak point. Unless the coders give us separate metrics for each catcher, it's not feasible to distinguish all the factors.