Monthly Archives: July 2012

Instant replay in tennis

This afternoon, I tuned in for the last two games of the Wimbledon semifinal between Andy Murray and Jo-Willy Tsonga. Andy Murray won the match, making him the first British male finalist at Wimbledon in 74 years (no pressure, Andy!).

The winning point was a bit strange, however. Murray hit an aggressive shot that was a tough call for the umpire. The crowd exploded, but then quickly realized the ump called it out. No matter. Murray put a finger in the air and challenged the shot. Under tennis replay rules, players can challenge in or out calls, and the disputes are decided by the Hawk-Eye ball tracking system. Hawk-Eye uses high frame rate cameras to map the trajectory of the ball. The Hawk-Eye trajectory showed the ball nicking the outside of the line, and Murray was through to the finals!

I asked my buddy Tony, a staunch replay opponent, whether he would have felt bad if Murray had lost the match in the absence of replay review. He said no, because he guessed the tennis replay system faces precision issues. This is his standard “blades of grass” complaint. On extremely close plays, there is no way to tell whether a ball (or player, in other sports) is in or out, because it comes down to the deformation of the ball on impact, individual blades of grass, and lack of precision in painted lines.

I set about to prove him wrong, under the premise that a computer-driven system like Hawk-Eye would have definable precision. In one way, I was right. Hawk-Eye’s average error is 3.6 mm. But if that’s the case, why is it used to¬†make calls that are well within it’s margin of error? Continue reading

My Imaginary Baseball Team: The Portland Peskies

During the NBA season this year, I wrote up some parameters for an alternative way to build an NBA winner: The Seattle Scientists. The idea behind the Scientists is the same old Moneyball methodology for small market teams — find the undervalued assets and spend your money there. In the NBA, my buddy Tony and I think effort, defense, and intelligence are the assets to focus on. In the the MLB, there are some related options: bunting, speed, and defense again. We settled on the Portland Peskies for this thought experiment (an over-educated city that would appreciate a non-traditional team), though the Indianapolis Institute and the Las Vegas Vig (“You can never beat the house!”) were also in the running.

It’s no coincidence that I’m writing this while my Tigers play their old nemesis the Twins. The Tigers (outside of Quintin Berry this year) never have any hitters that would fit the Pesky mold. But Twins outfielder Ben Revere (currently snagging a tailing line drive off his shoe tops) would be on the Peskies’ radar for sure, as would Alexi Casilla and Denard Span. Revere has 6 bunt singles this year on 13 tries and 16 steals Continue reading