Software allows researchers to compute a soccer player's value to his squad

Tuesday, June 22, 2010

Measuring the value of teamwork

Picking a fantasy soccer team is tough. Compared with other professional sports, soccer is short on statistics for each player's contribution to the game. Unlike strikeouts, passes completed or free throws, play-by-play stats for soccer are usually collected only for big matches. So fans have to rely on sports commentary, personal preference and guesswork.

But if you're trying to manage your own fantasy World Cup squad, don't throw in the towel quite yet. Researchers have devised a way to quantify an individual soccer player's skills as well as overall team performance. The results of the year-long study were published last week in PLoS ONE, a journal published by the Public Library of Science.

Luís Amaral, a chemical and biological engineering professor at Northwestern University and senior author of the paper, had graduate student Josh Waitzman design software to capture every play from the 2008 European Cup Web site. With Jordi Duch, an assistant professor at Universitat Rovira i Virgili in Tarragona, Spain, they created a system that calculated how each player performed.

Did players successfully pass, block, attack, score or set up a teammate to make a goal? These statistics could characterize a player as a ball hog, a shrewd strategist or an overall star. The results of Amaral's objective calculations turned out very similar to the subjective assessments of team managers and sports analysts.

"Our metric could be used to objectively quantify and compare the performance of players from different generations," Amaral wrote in an e-mail, "and in different competitions."

And, he said, it could apply outside sports. "Soccer is sort of a microcosm of what goes on in other contexts in which team interactions occur," Amaral said, teams such as students collaborating on class projects or management consultants approaching a business problem.

So what should you look for when choosing your picks for the World Cup finals July 11? Amaral says a player's individual strengths should enhance the team's overall performance. Players who fight to win the ball and those who make precise passes to the best-positioned teammate matter more than those who do crowd-pleasing tricks that add little to the game.

Big-name players such as Portugal's Cristiano Ronaldo and Argentina's Lionel Messi "can't do it all by themselves," Amaral added. "You need the right teammates."

-- Leslie Tamura

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