Tuesday, April 23rd, 2019

Baseball Statistics: BABIP Updated

April 19, 2010 by  
Filed under Statistics and Analysis

When we last visited this subject (see link here), there was considerable debate whether John Lannan’s abnormally low Batting Average for Balls Put into Play, or BABIP, was a statistical anomaly or whether there was something inherent in Lannan’s pitching technique and/or location that causes him to have the lowest BABIP in the league over the past two years–.275.

Recalling from the previous post that the premise behind this statistic is that a pitcher cannot control what happens after a pitch is put into play;  that luck is largely responsible for an unusually high or low BABIP.   On the other hand, batter’s BABIP can fluctuate more wildly because some elite hitters have a propensity for line drives or some hitter’s fleet-footedness can cause likely outs into hits.  However, it is commonly held that a pitcher cannot do much to influence their BABIP.

The league average is somewhere between .290 and .300 and a pitcher whose BABIP is substantially higher than this, say .330, is said to be unlucky and, based on the law of large numbers, is likely to regress (i.e. improve) back toward the league average.   Conversely, if a pitcher’s BABIP is unusually low, say .275, (like Lannan’s) it is thought that they have been lucky and future performances will move back to the league average.

I got to observe John Lannan first hand at last Friday’s game between the Washington Nationals and the Milwaukee Brewers.  (See the picture to right of Willie Harris wearing the Jackie Robinson #42.) Lannan ended up pitching 7 innings and giving up two earned runs.  Although Lannan got a no-decision, Washington eventually won the game 5-3.

Now let’s calculate Lannan’s BABIP. During Lannan’s 7 innings, he faced a total of 31 batters.  Taking away his 3 walks, leads to 28 at bats.  From that, we subtract both HRs and Strike Outs since neither of those types of results can be defensed.  This leaves a total of 22 batters.  He gave up a total of 7 hits from which the home run is also subtracted giving a total of 6 hits.  Finally, dividing 6/22 gives a BABIP of .273 exactly the superior BABIP which has drawn so much attention to Lannan.

Stay tuned.  I know the Sabermetricians and stat jockeys will be.

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