簡短概要：
Pitch f/x系統顯示主審的好壞球判決這七年來年年進步
證據也說主審的好球帶比以前更大，而且他們還會型塑心目中的好球帶
所以打者跟投手賽前必須知道這個主審的口味有多大多怪
現在有越來越多的聲音要求用機器人主審取代人肉主審
但是主審也在進步，他們的錯誤率比15-20年前更少
賽後他們還會立刻接到一份通知告訴你今天漏了哪幾顆好球、判了那些壞球為好球
圖一：http://li.tl/v/uO9n
這張圖顯示整體素質是進步的，但是好的還是很好，爛的還是很爛。Tim Welke是被數據認
定為最爛的主審，Barksdale則是最好的主審。Barksdale平均每場能比平均水準的主審多
判決出五顆正確的好球，Tim Welke則比平均低五顆左右。
圖二：http://li.tl/v/uO9e
好球帶以內的好球篩檢率顯著提升，壞球的篩檢率沒有太大的波動
雖然Lance Barksdale在好壞球判斷上面很強，但是不代表他整體的判決能力夠好。好壞
球只是一部分，熟知比賽規則、守備判斷、如何處理突發狀況也都是主審的重要課題。而
現實上，在季後賽這類緊繃的場合所派出的裁判組合並不一定是採用好球帶判斷精確做挑
選。比如去年的美聯冠軍系列賽，這場比賽派出一口氣出動精確度排名第70,71,76的裁判
(而排行榜總共只有79名裁判)。
Dusty Dellinger knows how difficult it is to be an umpire. “There’s an old
saying that they expect you to be perfect from day one and get better,” the
former Major League Baseball official said over the phone. As the director of
Minor League Baseball Umpire Development and the Minor League Baseball Umpire
Training Academy, he knows how elusive perfection can be.
Correctly calling 140 pitches flying 90-plus mph and breaking six inches or
more is a near-impossible standard. And when mistakes are made, players and
managers aren’t bashful. Jonathan Papelbon said D.J. Reyburn should “go
back to Triple A” after a confrontation over balls and strikes. Joe Girardi
complained about inconsistency. Larry Andersen did too after he retired,
labeling the men behind the plate arrogant. You don’t have to look too hard
for more examples.
That’s led plenty of people to wonder when robots will come for the umps’
jobs. But lost amid those blue-sky dreams is what’s happened to the way we
judge the blue behind the plate. Technology has changed how we can evaluate
umps. It shows that umps are getting better, that there’s a significant gap
between the best and worst, and that the best umps aren’t working the
biggest games.
After every game, umpires receive a report from the league office that
informs them about their accuracy, their correct calls, and the ones they
missed. Pitchers, hitters and fans have near-instant access to information on
an umpire’s accuracy, too. The chart below shows the accuracy rates for
calling balls and strikes for each ump since 2008, when MLB installed the
PITCHf/x tracking system in every stadium.
Umps are getting better, and they’re also remarkably consistent. An ump who
makes more accurate calls in one year will likely do the same the next; an
ump who misses more calls in a given season will likely be as bad the next.
Umpire accuracy is more steady than a player’s batting average or a pitcher’
s ERA, and as consistent as OPS (on-base plus slugging) and wins above
replacement.
To see how this works, look at the performance of Lance Barksdale and Tim
Welke. While they both follow the league’s general trend of increased
accuracy — more about that later — they have, respectively, been one of the
best and one of the worst umpires over the past seven years.
The difference between Barksdale and a league average ump is about five
correct calls per game; the difference between Barksdale and the league’s
worst umpire is closer to 10 calls a game. On average, that’s about one
judgment call per inning that a good ump is getting right and a bad ump is
getting wrong. That might not sound like much, but if once every six outs a
batter gets another swing after a third strike that wasn’t or a pitcher
strikes a hitter out on a pitch that’s actually a ball, you can start to see
the impact.
Given their differences, umps develop reputations. Near the end of infielder
Mark DeRosa’s 16-year career, he knew what to expect from the umpire calling
balls and strikes. “You gain knowledge over the course of being in the big
leagues for the course of a couple of seasons,” he said. “You understand
which umpires are a little bit wider in their zone, who are a little bit more
north-south, who’s going to force the pitcher to come tight.”
Before games, he and his teammates would even talk about what they could
expect during the game: “A comment would be passed back and forth, whether
we should be pulling the trigger tonight or ‘this guy is normally a hitter’
s umpire and likes to force the pitcher to come back over the plate, so let’
s be a little bit more picky with what you’re going to swing at.’ ”
An umpire who understands what calls he is missing is an ump who can improve.
“It was amazing how my perspective of the strike zone changed when I got
this technology,” Dellinger said. “I thought pitches were on the plate,
until you get that data back. You see that some of those pitches were not on
the plate. It wasn’t something that was done intentionally. It was just your
perception of the strike zone. I was able to quickly make adjustments based
on having that information, which was huge to me.”
Seeing the data, however, can make fans less charitable. “They see a pitch
that is out of the box, and they think, ‘Aw, he’s a bad umpire,’ ”
Dellinger said. “I’m thinking, ‘You should have seen it 15 or 20 years
ago.’ ”
He’s right — ump accuracy has improved since 2008. But it has been on only
one type of pitch: strikes.
While umps call balls no differently than they did seven years ago, they’re
accurately gauging strikes at much higher rates. This distinction is so large
that Brian Mills, a professor of tourism, recreation and sports management at
the University of Florida, cites the increasing size of the strike zone as
accounting for about half of the league’s 50-point drop in OPS since 2008.
In other words, steroid testing isn’t the only change responsible for MLB’s
drop in offensive output. It’s also more called strikes.
While the league and the umpires association have access to data showing that
specific umps tend to be better at calling balls and strikes, it does not
appear that they use this information to reward those who are the most
accurate with choice assignments, like the All-Star Game or the postseason.2
According to Peter Woodfork, senior vice president of baseball operations,
balls and strikes play a role, but don’t write Lance Barksdale’s name into
your World Series scorecard just yet. “Once you meet a standard, you’re in
the mix,” Woodfork said, likening the selection process to that of the NCAA
tournament. Assignments are doled out using a mix of analytics and judgment:
“Balls and strikes is taken into account along with field work, rules,
instant replay and handling situations. Professionalism also factors into
grading umpires. The plate work may carry more weight in the evaluation, but
they are all important.”
If plate work is important, it hasn’t shown in playoff assignments.
According to numbers from BaseballSavant.com, umps who were No. 70, 71 and 76
in the accuracy rankings (out of 79) called balls and strikes in the ALCS
last year, with only one of the top 10 umps receiving a league championship
series or World Series spot. And this more exhaustive look at umps also finds
that postseason spots do not appear to be linked to regular-season
performance.
“Like any other profession, you can go up and go down, but the consistency
over time often helps,” Woodfork said. “We don’t ignore what you’ve done
in the past, but that year carries the most weight.” If that’s true, expect
our old friend Barksdale to receive a high-profile opportunity, as his 90
percent accuracy rate through July 1 is far and away the best single-season
number in our data.
But while decisions on postseason spots won’t come for several weeks, MLB
has already had one opportunity to reward an umpire for past performance,
getting to pick a home plate umpire for July’s All-Star Game.
It chose Tim Welke — the same Tim Welke who has consistently had one of the
league’s worst rankings since 2008.