Reality Check: Good Eye, Bad Eye

(I am making a minor change to these "Reality Check" posts. Rather than base the title on the speaker, I'm going to change it to the subject matter. My goal isn't to single out people who say something that's wrong or right, but to figure out what's accurate.)

The Wall Street Journal has a pretty good sports page. That's all it is, one page, but the paper has smart and clever writers. One of the daily features is a column called "The Count" that uses numbers to illustrate a point. Today's The Count is called "Who Has the Best Eye in Baseball?" To spare you the suspense (though the link isn't behind a paywall), the writer concludes that it's Freddie Freeman of the Braves. Why? Because of batting title qualifiers for last year, Freeman took the most balls per called strike, 4.99. In other words, when he didn't swing, it was five times more likely to be a ball than a strike. That was way ahead of No. 2, The Rangers' Josh Hamilton, at 3.88, and No. 3 Pablo Sandoval of the Giants at 3.76.

One of the key questions you always need to ask when doing statistical analysis is, "Am I measuring the right thing?" The answer in this case is should be, "Anything that claims that Josh Hamilton and Pablo Sandoval have a good eye is probably not measuring the right thing." Hamilton is a notable free swinger, and as for Sandoval, he was the subject of one of the funniest articles last season on Baseball Prospectus. Last year, major league hitters swung at 46% of all pitches. Of the 140 players who qualified for the batting title (502 plate appearances), Freeman swung the tenth most frequently, 55%. Hamilton, at 56%, was seventh. Sandoval's 57% was third. So the top three cited by the Journal were also among the most prolific swingers. Do they have a good eye or don't they?

I think the problem lies in the Journal's methodology. You can achieve a high ratio of called balls to called strikes by never swinging at pitches outside the strike zone. That would increase the numerator in the called balls/called strikes ratio. Or you can swing at every pitch that's in the strike zone. That would reduce the denominator in the ratio. Sure enough, Freeman swung at 86% of pitches in the strike zone, way more than any other player. Hamilton was third, Sandoval fourth.

But does that mean you've got a good eye? Sandoval swung at 45% of pitches outside the strike zone, second most in the majors. Hamilton's 41% was ninth. Freeman was 36th, at 35%, but was still above the league average 31%. That doesn't seem discerning, does it?

Say a pitcher throws 10 pitches to a batter, half of them balls. One batter swings at four of the pitches in the strike zone and two of the pitches outside the zone. By the Journal's methodology, his batting eye would get a rating of 3 balls / 1 called strike = 3.00. Another batter swings at three of the pitches in the strike zone and none of the ones outside the zone. The Journal's rating would be 5 balls / 2 called strikes = 2.50. The former batter would be judged to have a better eye by the Journal's metric. Wouldn't you think that the guy who doesn't swing at pitches outside the strike zone is more disciplined? I would.

Here are the top ten by the Journal's methodology and mine, lowest percentage of swings outside the strike zone.
 Balls per Called Strike      % Swings Outside the Zone
 1. Freddie Freeman  4.99     1. Joey Votto       20.0%
 2. Josh Hamilton    3.88     2. Marco Scutaro    20.1%
 3. Pablo Sandoval   3.76     3. Jason Kipnis     21.6%
 4. Miguel Cabrera   3.72     4. Nate McLouth     21.8%
 5. Chris Davis      3.45     5. Matt Carpenter   22.1%
 6. Brandon Belt     3.45     6. Shin-Soo Choo    22.1%
 7. Carlos Gomez     3.17     7. Coco Crisp       22.5%
 8. Matt Holliday    3.10     8. Russell Martin   22.8%
 9. David Ortiz      3.09     9. Jose Bautista    23.2%
10. Domonic Brown    3.00    10. Dan Uggla        23.2%
Source: Wall Street Journal, FanGraphs

Certainly, the list on the left is much more formidable offensively. But that's not the question. The question is, who has the better batting eye? I'd give the nod to the guys who don't swing at pitches outside the strike zone rather than those who swing at everything, in the zone and out.