The folks over at Baseball Prospectus are the standard bearers of the Bill James School of Baseball Analysis. They've been doing it longer and better than just about anybody in town. And in a world where baseball journalism still trades, for the most part, in the kind of vague, subjective"gut feel" nonsense and loud, colorful metaphors of PTI or Mike and the Mad Dog, its nice to know that BP is out there with a pile of data and a little rigor, takin' er easy for all us sinners.
Unfortunately, as BP has become more successful and therefore expanded its coverage, it has taken on a bit of dead wood. This is only natural. Expand the league enough and performance averages dip--its why people talk about contracting the Rays or going back to the four-man rotation.
In BP's case it's Marc Normandin, a college kid from Massachusetts who through some combination of fellatio and nepotism managed to land a gig covering the "Fantasy Beat." You'd have to slog through a bit of his stuff--which manages to be both overly technical and shallow, go figure--to get the full effect of his mind-dulling mediocrity, but I can give you a taste.
In his recent "Third Base Review", Normandin talks about valuating the Red Sox' Mike Lowell for the '08 season. He says:
"Despite a pedestrian liner rate of 18.1 percent, Lowell's BABIP was .342, well above the league average and his expected BABIP of .301. Adjusting his line for this, Lowell should have hit around .283/.337/.460, which looks a lot like his 2006 performance. Let's also not forget that Lowell hit .373/.418/.575 at Fenway last year, and just .276/.339/.428 on the road. If you draft him, you might want a backup plan for road games. This also means you don't want to draft him too early, since he can't handle the position for you well enough on his own."
Ok, Marc, so Mike Lowell hit above his BABIP expectations (here using the quick and dirty .120 + LD% formula), and we should expect him to regress to the mean. But then you mention his home/road splits are out of whack...Any thought to the idea that there is something besides blind luck linking the two?
One obvious place to start is to note that the home/road splits in AVG/OBP/SLG are pretty tightly linked with his BABIP splits. Lowell hit .382 on balls in play at home versus just .293 on the road. That is, based on the "expected BABIP" he actually got cheated out of some hits on the road. Now, a curious mind might wonder why this should be so. If Normandin had ever, say, watched Lowell play a game in his life (he's allegedly a Sox fan), a moment's reflection might have resulted in a little white light--or perhaps a large, forest green wall--appearing somewhere in the imagination centers of his cortex.
Take a look at Lowell's extra base hits at Fenway Park:
You can find Lowell's complete spray charts here.
Notice anything interesting? Me either.
I should point out that I'm not the first, or the twelfth, guy to make this point. It's been a baseball blog staple for as long as Lowell's been doing it. Nor is my idea necessarily to skewer Normandin (at least 80% of my vitriol is sour grapes). Rather, I wanted to use this first post to suggest what this blog will NOT be.
Let me explain. Normandin essentially recommends Lowell as a "sell" because he assumes that the expected BABIP model is a good one and that divergences from it are the result of noise or "luck."
Yes, adding .120 to LEAGUE AVERAGE LD% does give something close to LEAGUE AVERAGE BABIP. But drawing conclusions from this about individual players is a pretty pedestrian instance of the ecological fallacy. (I'll do some more work later that shows that the model only works well for hitters with certain other tendencies.) But for the moment lets focus on the second assumption: that divergences from past, mean or "expected" performance levels are due mostly to luck.
Baseball history has shown this is an OK assumption to make--all other things being equal. But it didn't take much imagination to see that all other things weren't equal in the Mike Lowell case. The idea among casual sabermetricians (and, occasionally, professional ones) seems to be that a given player is essentially his Strat-O-Matic card--a pie sliced up into plate-appearance outcomes "weighted" to reflect that players tendencies.
But the weights can change, not only as context changes and players fluctuate around their personal peaks and means, but also because they make adjustments. They have gameplans. They react. Mike Lowell didn't hit .320 because of noise in the system, or because of the confluence of luck. Mike Lowell hit .320 by shortening his swing and uppercutting everything toward the Monster in Left. Mike Lowell knows it, opposing pitchers know it, every two-bit baseball blogger in the world knows it. The only person who doesn't seem to know it is Marc Normandin.
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