Quantifying and predicting the outcome of soccer games

Ngozi Ekeledo

Josh Waitzman and researchers for the Amaral Lab are caught up in World Cup soccer mania just like the rest of the world. Except their fandom starts with numbers and analysis.

Waitzman, a Northwestern graduate student, co-authored “Quantifying the Performance of Individual Players in a Team Activity” with McCormick professor Luís Amaral. The results of the paper help put into perspective a sport that often doesn’t bank upon hard data.

“For baseball, someone’s going to have 15 different ways of calculating how likely it is for someone to get a hit or on base and do something really good for their team when they get up to bat. No one really has a way of doing that for soccer,” Waitzman said. “It’s just who people get excited about when they watch or who has the biggest contract.”

Waitzman said the group uses the software as a way of examining existing data rather than predicting it.

“We’re not going to say we have the best way to bet a million bucks on the outcome of the World Cup, but I think it is a good formula for a sport like soccer where you don’t have a lot of data to go off of.”

The software was first created to analyze the 2008 European Cup tournament through quantitative measures like the number of passes made between teammates, Waitzman said. As well, the group analyzed and mapped out results based on players’ shooting information, according to a press release from the NU NewsCenter.

“One can get a better sense of individual contributions by analyzing how they interact with the team through the quantifiable measures available,” Waitzman said in an e-mail.

“This certainly constitutes a rough-cut view of the nuanced interactions between people, but gets us a lot closer to understanding how groups of people work together.”

The group’s findings, though, did reveal that many of soccer’s most elite and recognized players weren’t necessarily the most valuable players in terms of contributions for their team.

“How the numbers work out in the paper, the two players we actually pinned as the two best performers in the (Euro 2008 tournament were) Xavi Hernández and Sergio Ramos, and they’re both on the Spanish team,” Waitzman said. “Not too many people knew that either (player) did an exemplary job.”

The study’s results opened up a debate: salary discrepancies. With soccer celebrities like England’s David Beckham and Portugal’s Cristiano Ronaldo becoming more well-known for their time off the field, how can hefty paychecks be rewarded to the players who aren’t as popular?

“I think there’s going to be some lack of correlation between how people are doing and the salaries they’re getting paid, but I think for Sergio Ramos and his agents, (the analysis) is a good quantitative measure for them to be able to go into negotiations and say, ‘This guy’s really doing a good job for the team. You can see from the number of goals and assists that they’re really contributing to the team’s effort and you should pay them more money,'” Waitzman said.

For soccer fans like Eddie Siegel, though, ticket sales may be a more accurate method of determining salaries for these big-time players.

“You don’t pay a bunch of money for a ticket to see no-name players, and you’re not necessarily a fan of a team because of a couple of backup players,” the Weinberg senior said.

Siegel, the director of education for the NU Sports and Business Research Club, said that despite the analysis, ultimately the popular players are the ones who bring in the most financial success.

“These big name players bring so much revenue to the clubs, and that’s why you have them on your team. You think they’re overpaid, but they’re giving the most action for their team,” Siegel said. “If you want to sell tickets, you need the Wayne Rooneys and the Ronaldinhos.”

Many of the same soccer stars Waitzman and members of the group analyzed are participating in the World Cup that’s currently taking place in Johannesburg, South Africa. Even though the paper used analysis from the 2008 Euro Cup, World Cup fans are in luck-statistics on any individual player and analysis of all of the World Cup matches can be found on the Amaral group’s website at amaral.northwestern.edu.[email protected]