Study tries to evaluate performances of soccer players

A Northwestern professor says he's found a way to objectively evaluate players in a sport with few statistics because of the rarity of goals.

By

Rachel Cohen, AP

Wed, Jun 16 2010 at 7:02 PM

Related Topics:

Research & Innovation

RANKING SOCCER PLAYERS: According to the study, the best players would be the ones who most often touched the ball as part of a sequence that resulted in a shot. (Photo: ZUMA Press)

Xavi Hernandez was voted player of the tournament after Spain won the 2008 European Championship. Teammate Sergio Ramos didn't even make the all-tournament squad.

Yet they tied as the two best players at Euro 2008. At least according to a study out of Northwestern University's engineering school, which tried to quantify the performances of soccer players.

The report was published Wednesday in the scientific journal PLoS ONE.

Luis Amaral knows he isn't exactly unbiased when it comes to watching his beloved Portugal. The Northwestern engineering professor wanted to find a way to objectively evaluate players in a sport with few statistics because of the rarity of goals.

"When things are going well, I think they're playing better than they truly are," Amaral, the study's senior author, said in a phone interview Tuesday not long after Portugal tied Ivory Coast 0-0 in a World Cup match. "When they're not going well, I'm probably harsher than I should be."

Amaral and colleagues Jordi Duch and Josh Waitzman did a computer analysis of the play-by-play from each Euro 2008 game. The best players would be the ones who most often touched the ball as part of a sequence that resulted in a shot.

Of the 20 players with the highest scores for the tournament, eight made the all-tournament team. Amaral said that indicates the computer analysis is an accurate tool.

He believes it would be most valuable for scouting lower-level events and comparing players across different leagues and different seasons. Just as statistical analysis has influenced how baseball teams spend their millions, he predicts soccer clubs could follow suit.

"You start to ask, Are these players you're paying this amount of money to actually performing at that level?" Amaral said.

He suggested this type of analysis could also be helpful in basketball, even though the sport, unlike soccer, produces a plethora of stats. Assists are a widely used indicator, but what about the pass that led to the pass that led to the score?

These evaluations could even extend into business, measuring the individual contributions of employees working as a group.

Spain's Ramos may want to show this study to any potential future employers. The Real Madrid defender got off to a rocky start at Euro 2008, getting beat for a goal against Sweden and arguing with his coach at a practice.

But he wound up being a key cog in Spain's run to the championship — and apparently was just as important in his team scoring all-important goals as the much-honored Xavi.

The top 20 players at Euro 2008 as determined by the computer analysis:

T1. Sergio Ramos, Spain

T1. Xavi Hernandez, Spain

3. Marcos Senna, Spain

4. David Silva, Spain

5. Wesley Sneijder, Netherlands

T6. Deco, Portugal

T6. Joan Capdevila, Spain

8. Cristiano Ronaldo, Portugal

9. David Villa, Spain

T10. Armando Petit, Portugal

T10. Cesc Fabregas, Spain