Wednesday, May 20, 2009

Fun with small samples

Alex Rodriguez, 2009 Season through 5/19/2009:

AVG: 0.194
OBP: 0.383
SLG: 0.611
OPS: 0.994
ISO: 0.417 (!)
BABIP: 0.083 (!!!)

It's pretty hard to be valuable when you get hits on less than 10% of the balls you put in play. You essentially have to do nothing but walk and hit homeruns, and that's what A-Rod is doing. It will all even out, of course, but for now, that's a pretty damn funny line.


Lisa said...

You need to expand your explanation of abbreviations, or this ole gal will assume OPS means optimal popularity score, ISO means individual swearing option, and BABIP means bring a bat if possible... Am I right on any of these?

John Lynch said...

ISO is explained on the right hand side of my blog. An ISO of greater than .300 indicates superb power. Greater than .400 is pretty silly.

BABIP is Batting Average on Balls In Play. Roughly speaking, it is what a player hits in at bats where a ball must be fielded. It is generally higher than a normal batting average (since strikeouts are removed). It is also more sensitive to chance than normal batting average. A-Rod's BABIP at the time is stunningly, impossibly low. It's also quite silly actually. That and the ISO are what drove the post.

Even in mainstream circles, OPS is generally common enough not to warrant explanation. It means On base percentage Plus Slugging percentage and that is exactly what it is. I don't use it much myself because there are better metrics, but it is a decent back of the envelope measure that many people are familiar with. A rough scale is that greater than 1.000 is a Hall of Fame level season; greater than 0.900 is an All Star level season; greater than .800 is a good season; 0.750 is near average; less than .700 is a poor season; less than .600 is putrid.

The point here is that A-Rod had been enormously productive despite the fact that he was almost never getting hits when he didn't hit the ball over the fence. Hence, he had a normal (for A-Rod) OBP, SLG, and OPS, but a enormous ISO and a tiny BABIP. It's just a really funny set of numbers.