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April 13, 2005

Lies, Damned Lies

Change-ups and BABIP

by Nate Silver

At its core, the scientific method is about attempting to explain observed phenomenon. A lot of sabermetric innovations have been the result of a clever researcher playing around with a large dataset, molding the data in a way that nobody has before, and emerging with a result that is both exciting and readily verifiable.

Voros McCracken started by observing that certain well-known pitchers were not very consistent in their ability to prevent hits on balls batted into play; Roger Clemens or Randy Johnson might rank at the top of the charts in BABIP one year, and on the lowest rung the next. As he soon discovered, this was not some isolated characteristic of Clemens or Johnson; throughout the annals of baseball history, the vast majority of major-league pitchers had demonstrated almost no ability to regulate their BABIP.

In that spirit, let me point out a couple of observations of my own:

1. The White Sox' Shingo Takatsu had a 2004 BABIP of .207, an extremely low figure. Only one pitcher who threw 50 or more innings last season had a lower number. Takatsu also has a history of posting low BABIP numbers in Japan.

2. Takatsu throws a change-up that registers in the low 60s, one of the slowest pitches thrown in the major leagues today; only knuckleballs and an occasional Orlando Hernandez lollipop take longer to reach the plate.

3. Knuckleball pitchers, as McCracken and other researchers have demonstrated, are an exception to DIPS theory, and do consistently post BABIPs lower than league average.