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Thursday, July 2, 2009

Stats team have fingers on pulse

Photo Titled Match stats
Match stats being collected on Centre Court.
The crowd is silent as Serena Williams gently tosses a ball into the air. Like a mini glowing sun, it momentarily hovers above her head before it starts its rapid descent towards earth. Whack! In the blink of an eye the ball deforms, looking more like a miniature rugby ball as it absorbs kinetic energy from Williams' racket before it rockets over the net towards a waiting Elena Dementieva.

The first ladies' semi-final has begun, and milliseconds later, millions of screens around the world reveal that the service speed was 96mph as Serena goes up 15-0 with an ace.

Technology has changed the way we look at the world, and tennis, like any other sport, is no different. As the match progresses, the spectators are blissfully unaware of the array of information logged and disseminated worldwide every time a point is won or lost.

The process relies on the collection of raw data, and until laser scanners, GPS tennis balls and rackets with motion sensors grace the courts, most of this is collected using a manual entry process.

In the name of research, I find myself alongside three of IBM's data collectors, peering down on Serena and Elena from the fifth floor of Centre Court. The data collectors are all accomplished tennis players. It turns out it is easier to teach a tennis player how to do data entry than the other way round. A requirement of the job is to be rated 3 or better on the International Tennis Number scale, which officially classifies them as "advanced players".

All six of the show courts have three data collectors monitoring the action. The outside courts have just one, unless the match is televised live, when two are used for good measure.

As Williams and Dementieva rise from their changeover, the room goes silent as one of the statisticians, an expert in categorising serves, presses a button to power up the radar gun in anticipation of the next delivery. "Wide in, Forehand In, Point to Williams, Backhand drive winner, Baseline, Thirty Love", calls out one of them as the other two frantically enter the details.

This is not a job for the faint-hearted for, as soon as they press the enter button, the numbers are beamed out to glowing screens worldwide.

All of the data traverses a complicated path of copper and optical fibre, through numerous routers and patch panels, all at the speed of light until they arrive at IBM's onsite statistics office. The figures are stored on redundant databases where they are readied to be released to the world.

The live scores pages on are just one of the places these stats are destined for. At the end of every match, the figures are collated and made available for viewing via a match statistics link. IBM also produce graphics overlays for television broadcasters to place over the pictures they use.

When a point is challenged by a player, the stats team, in the name of speed, fill out the details in advance based on their own prediction of where the ball landed. If they are correct, the alteration only requires a press of the magic enter key. That is when the Wimbledon's stats experts go head to head with Hawk-Eye.

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