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View Full Version : Question about LD% stat


Moses_Scurry
05-24-2012, 09:03 AM
I've been reading a lot of blogs and boards where they talk about BABIP and LD% used in combination to determine whether or not someone is "lucky". I see this Line Drive % number, and it gets me thinking. Who determines whether a hit ball is a line drive or a fly ball? What are the parameters? If a batter hits a head-high shot between the SS and 2B that lands about 15 feet behind second base, is that a line drive or a ground ball? Is a home run always a line drive, always a fly ball, or determined at the hit? Does somebody at every stadium pronounce a hit a line drive vs. a fly ball or is it some guy at a central location that watches the video? What about a bloop duck snort?

These are the questions that pop into my head when reading about the more advanced stats.

doublem23
05-24-2012, 09:16 AM
I'm not sure if there's any true definition of what consitutes a "fly ball" and what constitutes a "line drive." FB/LD% is one of the least reliable of the new sabermertric stats. The one thing it does have going for it, though, is that all the data that has ever been published is tracked by a single company, Baseball Info Solutions, so at least it's coming from a single, consistent source. So you know what you see at one place should be the same data you see at another.

Generally, though, I get the feeling that whatever small errors there may be in overlap are generally small and even out over time. Maybe FB/LD rates aren't great for a guy with only 5 hits, but for a guy with 150 hits, it should be relatively accurate, much in the same way we analyze how effectively a pitcher throws strikes when they're being called by umps who we all know make a mistake from time to time, but over the course of 200 IP, those mistakes should even out.

fisk4ever
05-24-2012, 02:58 PM
I wonder if it has to do with hang time...visual observation, not measured. d. A can of corn would be a fly ball or pop up.

SI1020
05-24-2012, 03:27 PM
These are the questions that pop into my head when reading about the more advanced stats. I have a laundry list of them. One day I'll meet a committed stats person and we'll go over all the formulas. I hope anyway.

eriqjaffe
05-24-2012, 03:37 PM
I wonder if it has to do with hang time...visual observation, not measured. d. A can of corn would be a fly ball or pop up.Given who is measuring it, I doubt it is based on visual observation. It's probably based on some combination angle of trajectory and distance, which would be easy enough to measure.