Wednesday, January 27, 2010

More pitching randomness than just DIPS

Last month, Nick Steiner discovered something interesting: pitchers don't actually seem to pitch any worse when getting shelled than when getting batters out. That is: if you were to look at the types of pitches thrown, their speed, and their break, the shutout pitches look the same as the "give up five runs in three innings" pitches.

If that's the case, the implication is that the differences are batters, umpires, or luck. I think it's mostly luck. Previously, I argued that simulation games like APBA serve as evidence of that. The same pitcher's APBA card, with the same batters, can result in a shutout or a blowout just based on dice rolls, and the pattern of performance looks fairly realistic. I don't know of any studies on this, but I bet if you played out a random pitcher's season on APBA, and then you put his APBA first innings side-by-side with the first innings of his actual starts, you'd have a tough time figuring out which was which.

Anyway, Nick expands on the topic today, over at Hardball Times. He found a bunch of pitches that looked almost exactly the same: 2-1 count, nobody on, fastball following a fastball, righty pitcher, righty hitter, similar location, similar speed, similar break. Although the pitches and situations were almost the same, the results were wildly different: sometimes a strike, sometimes a ball, sometimes a home run, sometimes an out, sometimes a double.

The idea is similar to DIPS, which posits that what happens after a batter puts the ball in play is mostly out of the control of the pitcher. Nick is saying that, outside of the actual characteristics of the pitch, what happens to a it is also out of the pitcher's control. All the pitcher can do is put the ball in a certain place at a certain speed with a certain movement, and then it's up to the batter and umpire and random chance.

So, suppose a certain pitch in a certain spot on a certain count usually results in 0.1 runs more than average. If a pitcher threw 50 of those, and it turned out the batters hit them hard, which resulted in 10 runs instead of 5, you could assume those extra five runs were random, and not the pitcher's "fault". That would allow you to better project his performance in future years -- as a GM, you might be able to find some underpriced pitchers, and trade away your overvalued ones. Just like a "DIPS ERA," which evaluates a pitcher based on factors other than his balls in play, you could create a "PitchF/X ERA" which evaluates a pitcher based only on the qualities of the pitches he threw, rather than what happened to them.

To do that, I think more work needs to be done. There probably aren't enough samples in each "bin" to get you good estimates of the value of a specific pitch. You might have to somehow smooth out the data, so you can extrapolate as to how much a 95 mph pitch is worth compared to a 93 mph pitch (Nick found the slower pitch actually led to better results for the pitcher, which is probably just a statistical anomaly you'd want to fix). You'd also have to think about other things that this analysis doesn't consider: patterns of pitch selection, tipping off pitches, understanding batters' weaknesses, and so on.

But even without those caveats, I think this is something that could work, with enough reliable data.


What I find interesting about all this stuff is that it further formalizes the idea that most of what happens in a baseball game is luck. There is a tendency to treat a player's accomplishments as a direct manifestation of his skill, even in small sample sizes where it probably isn't. When Albert Pujols hits a home run, there's tendency to talk about how it was the pitcher's fault for giving him that pitch to hit, or why Pujols was able to recognize it and hit it out. Reality is probably different. I'd bet that a lot of Pujols home runs came on "good" pitches, in the sense that their expectation was zero or positive, but Pujols just happened to get good wood on them. And I bet you'd find more than the occasional weak ground ball on what was actually a juicy pitch to hit.

Because Pujols is random too. Given a certain pitch on a certain count in a certain place with a certain amount of break, Pujols is sometimes going to hit it out, sometimes he'll swing and miss, sometimes he'll ground out, and so on. It's all a matter of the probabilities coming together, like the dice rolls in an APBA game.

In "The Physics of Baseball," Robert Adair reports that the difference between hitting the ball to center field and hitting the ball foul is 1/100 of a second. No batter is so good that he can always time his swing to .01 seconds. Some batters may be closer to that than others: maybe one batter has an SD of 1/100 of a second, so that he hits the ball fair 2/3 of the time, and another has an SD of 2/100 of a second, so that he hits the ball fair only 38% of the time. Talent and practice and concentration can lower a player's SD, but not to zero. There's still a lot of luck involved even for Albert Pujols. Over a season, the luck will even out and he'll hit over .300, but in any given game, he could easily go 0-for-4, without there being anything wrong with his talent on that day.

The luck isn't just because hitting a baseball is hard. Think about foul shooting in basketball. Even the best players don't shoot free throws with much more than 90% accuracy. And free throws are shot under the exact same circumstances every time, with no opposition trying to stop you. Foul shooting is something every NBA player has been doing since childhood, over and over and over, and they still can't get much better than 9 times out of 10. Why is that? It's probably the same thing as hitting a baseball: you have to do a lot of things right, with your eyes and arms and hands, and if you're more than a certain bit off, the ball won't go. And humans just aren't biologically built to be perfect enough that we can be within those very narrow limits every time. If the trajectory of a successful shot has to be within 0.1 degree of perfect (I'm making these numbers up), and our bodies are good enough only to give us a standard deviation of 0.06 degrees, even after practicing for 15 years, then no matter what, we're still going to be missing 10% of shots. That's just the way it is.

As a player, your goal can't be to make 100% of your shots. I think that's impossible, based on the limitations of the human brain and body. What you *can* do is practice enough, and the right way, that you reduce your slight errors, your standard deviation from the "ideal" shot, as much as possible. You can also work to make sure that you're always at your best. If you're normally a 90% shooter, but in clutch situations your hands shake and you hit only 80% -- well, getting your clutch performance from 80 to the 90 percent you're capable of will be a lot easier, I think, than raising your non-clutch 90 percent to 91 percent.

But no matter what, whether you're a pitcher, batter, basketball player, goalie, or whatever -- there is a limit to how perfect or predictable you can get. The best you can do is to work hard enough that your practice and talent gives you the best possible APBA card you can get. After that, you're at the mercy of the dice rolls.

Glove slap: Tango

Labels: , , ,


At Wednesday, February 03, 2010 8:56:00 PM, Blogger Unknown said...

Phil, trying to find an e-mail for you and not succeeding. If amenable, could you drop me a line at evan.brunell AT Thanks!

At Friday, February 05, 2010 11:09:00 AM, Anonymous Anonymous said...

I always thought this was an interesting question. Is there a way to remove the luck and determine what is good pitching v. good hitting. MLB announcers to think (or say) that when teams score runs, the hitters are hitting well AND the pitchers are pitching poorly. I'd love a definitive method to determine good hitting from good pitching.

At Friday, February 05, 2010 12:55:00 PM, Anonymous Anonymous said...

Luck and randomness are terms that human beings use when they simply haven't figured out how to measure something precisely enough, or, in the case of quantum mechanics, it is impossible to measure. We may figure these things out eventually - many things in the past that were judged to be luck and random are now things that we can accurately forecast.

At Friday, February 05, 2010 5:53:00 PM, Anonymous Anonymous said...

You're going to tell me that Wade Boggs and Rod Carew didn't have any idea of where they were going to hit the ball? Or that Mariano Rivera is successful because of luck? That's one of the reason DIPS and BABIP are two more useless exercises in sabermetric self-glorification. Back to your mom's basements. Long live Murray Chass who actually knows something about baseball. If you want a game run by robots go right ahead.

At Friday, February 05, 2010 10:53:00 PM, Blogger AMusingFool said...

This is an interesting idea, but even if it does have some basis in fact (and my knee-jerk suspicion is that it does), it completely ignores the whole thing of "pitcher vs thrower". Ie: Not whether pitch X can be thrown, but also whether the correct pitch (delivery, speed, location, break) is chosen.

I think this deserves some study, but I'd be careful about trying to draw conclusions about specific pitchers (in particular, whether to sign a given pitcher) based purely on what you come up with.

Remember the old saying, "Hitting is all about timing; pitching is all about messing with that timing" (or whatever the exact quote was).

At Tuesday, November 02, 2010 12:39:00 AM, Anonymous Anonymous said...

I've known that baseball was based on luck since childhood. How many times does a pitcher get bombed with line drives and balls to the warning track or balls down the line that just miss yet he still pitches a no hitter? A few inches here or there or if played in another ballpark not only would he not have a no-hitter, he might give up 10 runs. Fly balls in one ballpark are home runs in others. Balls hit foul in one ballpark are fair in others. Balls are caught or go in for hits based on defensive positioning or just sheer luck. I can go on and on.


Post a Comment

<< Home