Tuesday, May 6, 2014

Great article on BABIP and xBABIP

We've gotten a bit heavy on stats lately, particularly predictive stats. While most of the stats we reference have been in existence for several years, they're just recently being thrown into the common, every day baseball lexicon. (Speaking of which, take a few minutes to look over this, and note the How Many Altuves shout-out.) I can't speak for the other writers around here, but I'm still learning how to work this data into my thoughts about player performance, which is why I really appreciate this article from Beyond the Box Score. Keep in mind, this is referring only to BABIP on the hitters' side, and does not go into a pitcher's control over BABIP. That's a whole other animal.

In particular, this excerpt got me to thinking:

But perhaps some of us have been far too literal when reading BABIP disclaimers in the past. We passively accept a .300 BABIP as the benchmark and expect results to fluctuate in accordance with the principles of regression. More importantly, the casual passerby will often treat BABIP as something a batter has little or no control over, but that's not the case.

There was a time not too long ago that this was the consensus opinion about the subject, but as more research has been done, we're starting to see things a little more clearly.

What was done here is, each hitter was broken down into his well-hit average (percentage of balls hit hard, regardless of outcome) and speed scores (which could indicate an ability to beat out a bunt or get an infield hit) to work up an expected BABIP, referred to as xBABIP. That was then compared to his actual BABIP in an attempt to look at, on an individual level, which hitters have been "lucky".

There are some fun charts and graphs, and a link to the information itself in the form of a Google Doc spreadsheet. From what they're showing, Chris Carter could be argued to be the 5th most "unlucky" hitter so far this season.

Now, the more curmudgeonly of our readers will say "But that's not what you guys were saying a couple weeks ago!" And those Grumpy McGrumpersons would be right. And it would be the first time they enjoyed life in a long, long time.

But how sad would it be if, when we're presented with new data, we simply threw it out the window and stuck to our preconceived "truths"?

No comments: