The $64,000 Q on "Sample Size" for INDIVIDUAL PLAYERS
Where is this guy going to end up? Will 100 more feet tell you?

 

I've never understood why people referred to Doug Fister's July 2010 as a "sample" of any kind.  How could Fister's performances in July 2010 relate in any way to the pitcher he was going to be in 2012?  ... yet Fangraphs insists on casting a player's MONTH as a type of 2% REPRESENTATIVE SAMPLE of his career.

If Nick Franklin comes up and takes 100 AB's for the Mariners, that's not going to be a "sample" of ANYTHING, except a very small sample of Franklin's skill level AT THE MOMENT.

It really is like watching a motorcycle zoom around through mountain passes, and you "sample" him going around one curve, and project his overall direction from that.  Is it not?

.........

Here's where we run into Gaffney's "moving target" problem.  He was careful to specify that he was most dubious about pop sabermetrics as they apply to roster construction issues.

James (and I) couldn't agree more.  You won't see Bill James casting much of an opinion on whether Nick Franklin should be called up or not.

Industry trends?  Sure, you can conclude that pitchers with 8K per game are better bets than pitchers with 4K per game.  Industrywide tendencies, those you can capture.  Roster construction?  Different animal, scientifically.

This isn't a quibble.  Sabermetricians' job seems to be to "sample" that motorcycle going around one corner, and then to forecast where he'll be in 4 minutes and 30 seconds.  Can we agree that another 15 seconds' worth of "sample" is useless?

.............

Sure, PECOTA will tell you that the last 10 motorcycles taking this turn ended up "averaging" a NW direction.  

You want to know that.  The problem comes when Rany Jazayerli insists you "correctly value" the path as NW'erly.

..............

... how were you supposed to use "sampling" to project Kyle Seager, one day before his ML callup?  His career arc took an unexpected direction when he collided with MLB pitching.

How would "wider sampling" have helped you project Raul Ibanez when he was 26, or Jason Varitek when he was 24, or Jesus Montero when he's 23?  Rauuulllll's career arc took an unpredictable turn in his late 20's.  No amount of high-speed photography, of his mountain turns, at age 25, would have helped you.

But we see pop sabermetricians, all the time, see a ballplayer called up for one month, and then start gravely discussing his future based on their "sample."

We don' have a sample of Jesus Montero's career, gennlemen.  His 2012-13 is not providing a certain fraction of data as to his 2016 outcomes.

Matt, I'd like your comment on this, if you're so inclined.

Comments

1
M's Watcher's picture

What I am confident about in projecting Franklin, should he get 100 MLB-TM at bats, is that if he does well, his trade value will increase. It still may not predict his future performance, though it may more likely be with another team. Until he's promoted, he'll be just another AAA prospect, a top one, but untested in the bigs. He's worth more with MLB success. If he fails, he's just not ready yet, but it shouldn't hurt his value. It's not like a cup of coffee compares to Smoak's 1500 PAs.

2

Suffice to say, the Yankees face enough media scrutiny that if you are an employee and you're saying anything that could be construed as a comment on a player of "interest"...on the industry trends, or especially on the Yankees...the media here in NYC will quickly pounce on it as a comment from an unidentified team source.
The unethical conduct of the media has gotten so bad now that the Yankees have a hard rule against blogging, tweeting, or public commenting to the press. It also suffices to say that I can't really do that and still enjoy being a Mariner fan. I am looking for alternative (less public) means of conversing with my friends in the Seattle blogosphere. I'm pretty miserable with this particular rule. So if anyone wants to talk baseball over Skype or another chat service...or through email if you lack the patience for that sort of thing...I would greatly appreciate the chance to stay in touch and talk Mariners and baseball philosophy. Doc...I don't want to post my email address here...you have my email address that I used to register with...can you pass it along to anyone asking for it?
I am sorry about this, all. Trust me...I'm not happy with it at all.

5

If you're interested in an old guy's views, get my e-mail from Doc and we can skype during key games - I have premium, which allows conference skype, so we could get more guys involved (up to 5, I think, but my bandwidth allows ~4).

6

I don't have a good address to reach you and I am hoping you can be a go-between here while I try to establish some connections during the games. Sorry to bug you...don't have another good way.

7

You'll always be a part of the Mariners community. Hope the Yankees gig takes you where you want to go, though. Just make sure if we ever meet in the playoffs you drop some bad sushi on the pre-game buffet table. That'll make up for the umpiring we'll get.

8

Maybe you can set up an incognito name at MC or something.  That totally BUMS me OUT, dude.  Grrrrrr...
At least we have confirmed what we always suspected about "unknown org sources" ... not that any bloggers around here would do that .....

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