THE BOOK--Playing The Percentages In Baseball

Sunday, February 24, 2008

Projecting Pitching Longevity Revisited

Another excellent, albeit incomplete again, look, by David Gassko, at whether and how we can project one pitcher to have a longer career than another, other than by our estimate of their overall pitching talent, as measured by something like regressed FIP (or simply a good context-neutral pitching projection).

Last time he debunked (not completely, mind you) the “conventional” (I put that in quotes because it also was/is the CW in sabermetric circles, or at least something that analysts occasionally mention in passing and it goes unchallenged) wisdom that high K pitchers have longer careers than similarly talented (overall) low-K pitchers, originally promulgated by Bill James, using some (severely) flawed research.

This time he looks at low and high BB pitchers and finds that the low BB ones have substantially longer (around 25%) careers.  This seems to fly in the face of his work last week, although apples and oranges (K rate and BB rate), or at least Macintosh and Granny Smith apples only, are being compared.

Hopefully, David will come back with some more work on the subject and not leave us hanging.

Speaking of “myths,” please tell everyone you know that, ballparks are NOT smaller than they used to be, at least since 1990.  I have been trumpeting this for a while now.  Jay Jaffee of BP gives us the net change in park dimensions (not fence heights though) from 1990 to 2007.  Guess what?  Parks are bigger now than they used to be!  The next time you hear a commentator tell us that run scoring and home run rates are up since the 80’s and early 90’s because of “smaller parks,” please call your Congressman or at least the radio or TV station from whence the broadcaster comes!