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Questioning QuesTec, II
2003-06-06 01:23
by Mike Carminati

ESPN featured the QuesTec Umpire Evaluation/Information System:

- First Peter Gammons explains what QuesTec is in a little video.

Don't bother listening to Gammons but check out the footage of the QuesTec system at work. Though Stinky Pete is bloviating there are a couple things about the QuesTec system shown in the video that I, at least, have not seen before. They show that there are cameras mounted on apparently the mezzanine are as well as the field level cameras that Curt Schilling is wont to pound. Also, the system's computer system shows the path of the ball from the top view, the side view, and the plate view (at least that's what each frame in the window displayed).

What do I make of this? Apparently, QuesTec follows the path of the ball as it approaches home; it does not just take a snapshot at one point at home as I was led to believe from what I had read. This is good because the strike zone is defined as the area above the entire plate and the path of a ball may mean that it is a strike as it passes the front of the plate but appears to be a ball when it passes the back. That would mean that a system that takes readings at the back of the plate would inaccurately call it a ball. QuesTec, at least in theory, would call it (correctly) a strike.

Also, QuesTec uses four camera angles apparently: two field level and two mezzanine, each with views from either side of the plate. Of course, four camera angles are better than two. One would need at least three to triangulate the position of the ball at a given time.

So there were positive signs. However, I am still concerned that the batter himself may block up to two of those camera angles (i.e, a field-level and a mezzanine level on the side from which he is batting). If that is the case, I do not believe that the other two camera alone can accurately triangulate the path of the ball at the most critical point, as it crosses home. As configurations of stadiums vary wouldn't the quality of the camera angles vary? I am also concerned about the manner by which the cameras determine what consititutes the ball is they determine its trajectory. If it's motion, then wouldn't it be pick up the batter's preparations to swing and potentially add those coordinates into the trajectory? Also, the vertical perimeter of the strike zone is established by a technician and relies directly on his accuracy. How do we know that he is accurately following the rulebook definition? How do we know he is doing it as the batter sets himself, not when he swings or just stands at the plate? How do we know that the system itself gives him an accurate enough picture that he can do his job effectively?

It's scary, but I think I agree with Gammons: The system has to be universal (i.e., installed in al stadiums) to be effective and it is still in the nascent stages and improvements to the sytem must be forthcoming. I do disagree with Gammons in his believe that 21-year-old operators must be replaced by ex-umpires. I would think retired umpires would be intimated, neo-Luddites in dealing with the computer-based system. They should be consulted, but a trained technician has to be the most qualified person to operate the system.

- Next, they have an overview of the QuesTec system. Included are the 10 stadiums that have QuesTec currently installed, a list that is both handy and dandy:

Bank One Ballpark (Arizona)
Fenway Park (Boston)
Tropicana Field (Tampa Bay)
Jacobs Field (Cleveland)
Miller Park (Milwaukee)
Edison Field (Anaheim)
Network Associates Coliseum (Oakland)
Minute Maid Park (Houston)
Shea Stadium (Mets)
Yankee Stadium (Yankees)

It then describes the system with some possible inherent detriments:

Multiple track points precisely locate the ball in space and time.

Well, "track points" are nice, but why not a continuous tracking of the ball. Wouldn't that be more accurate?

According to the New York Times, a computer technician sets the strike zone from a snapshot taken as the first pitch to a batter was on the way to the plate. That is used to measure whether the pitch was a strike or not.

So it's only set for the first batter. What if that batter is Austin Kearns or Richie Sexson? Wouldn't the strike zone be too big for subsequent batters? What if it's Tony Womack, wouldn't the established zone be too small for Randy Johnson. I'm not sure if this is correct since one repeated criticism by the umps is that repeatedly setting the strike zone changes a call within a game, an inning, or even an at-bat.

Actually, a latter bullet point indicates this:

The strike zone is established by a computer operator, so they say it varies from park to park, from at-bat to at-bat with the same batter and sometimes even from pitch to pitch.

The piece also states that QuesTec claims to be accurate within one-half inch, though it does not say in which dimension nor how that was benchmarked.

Lastly, it tells us the curve for umps:

Umpires have been told that if at least 90 percent of their calls do not conform with QuesTec calls, they are guilty of below-standard umpiring.

- Next, the Baseball Prospectus boys compare the percentage of balls, strikes, and home runs hit and the number of runs scored per QuesTec and non-QuesTec park. They also compared down to the ump. Their findings? First they found that QuesTec does not bring consistency. Hitters' umps (i.e., ones that call more balls) are not reined in but rather overcompensate and call more strikes:

Our numbers reveal that QuesTec has made a difference for individual umpires, each of whom has adapted to the system differently, and unpredictably.

The one thing that pitchers and hitters can agree upon is that it's not so important what sort of strike zone is called, so long as it is called consistently. It's possible that with proper training, proper calibration, and comprehensive implementation at all ballparks, the QuesTec system will eventually be able to provide for that. But it isn't there yet, and until it is, cameras everywhere will not be safe.

Of course, their study did not record what type of strike was called in each case. Since one goal is to eliminate the outside, off-the-plate, Eric Gregg strike and call the belt-high, 1977 strike, it is possible that umps are awarding strikes differently in the QuesTec and non-QuesTec stadiums.

- On the same page, Rob Neyer cites Robert K. Adair, author of The Physics of Baseball and a consultant that the umpires hired to find fault with the system. He likes the system though admits that there are still a few kinks to be worked out:

"The umpire's strike zone and the QuesTec strike zone are consistent, but in different ways. The umpires' strike zone is much wider than home plate: at least a ball width on the outside corner, and half a ball on the inside. And the umpires' strike zone is smaller by a ball and a half at the bottom, and half a ball at the top."
Meanwhile, the QuesTec strike zone does closely mirror the strike zone defined in the rulebook. It's true that the zone must be adjusted up and down for each batter, but Adair says the operators generally do a good job making those adjustments. What's more, while a certain number of pitches do give incorrect readings, "Operators are given leave to kick those out, and typically they tend to throw out six or seven pitches per game."

Adair's opinion does carry a lot of weight here because he is probably the foremost authority on the physics involved in a game of base.

- Lastly, there's are old friend Joe Morgan. Morgan agrees with me on a few points, which really scares me. He opines that the tool is best used as a training device. He also offers that it is not accurate across all stadiums:

I was invited to the umpire's room before a "Sunday Night Baseball" telecast. Umpiring officials showed me the QuesTec system and explained why they felt it wasn't accurate. And after seeing their demonstration, I could see what they were talking about (from ballpark to ballpark, similar pitches to the same batter were called differently by the computer).

Of course, the camera angles that the umps were using to determine this may vary from stadium to stadium as well.

Oddly, Morgan puts all his trust in K-Zone, ESPN's answer to QuesTec. Perhaps, he's just being a loyal employee but he sells it:

K-Zone, ESPN's strike-zone accurate to within four-tenths of an inch. I don't use it to grade the umpires but to demonstrate how the pitcher uses different parts of the zone or misses just off the plate.
I trust K-Zone because I know how it works and I know it's accurate.

However, he never explains why it's accurate.

I have to say that the more I read about QuesTec, the more faith I have in its accuracy. I still have a ton of issues though. I am like the E.G. Marshall character in 12 Angry Men, who holds out until he has answered every question about every shred of evidence. He finally does agree with the rest that the man is not guilty, saying, "I have a reasonable doubt now." Well, my process is the reverse. I want to remove the reasonable doubt. I'll let you know if I get there.

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