Best Team Not Guaranteed World Cup Success

Jun 12, 2010 — -- The World Cup offers fans of the globe's most popular sport the chance to thrill and agonize over the ups and downs of their nations' teams. For scientists, whether or not they are fans, it's another chance to collect data and test hypotheses about how close the final match results reflected the relative skill and performance of the two teams -- and if they used the best possible winning strategies.

When the dust clears after the World Cup concludes next month, it's likely that the champion will not be the team that played the best, said Gerald Skinner, an astrophysicist at the University of Maryland in College Park.

Following up on a lunchroom discussion with his avid fan tablemates, Skinner, who admits not being a great sports enthusiast, published a research paper in 2009 that worked out the details of his claim using statistical techniques familiar to astronomers. The findings backed up his posturing.

"It's not entirely a random process, but the result of an individual football match has got a very large element of chance and randomness in it," said Skinner.

The average World Cup match in 2006 featured a combined total of 2.3 goals. By analyzing the number of goals and their distribution, which is best described by a statistical phenomenon called a Poisson distribution, Skinner was able to show that if a match were replayed, the number of goals in a match and even the winner could vary considerably even if both teams played exactly as well -- partially because soccer is such a low-scoring game.

For a team that won by a commanding score such as 3-0, fans can be pretty certain that the better team won, but Skinner said that a 2-1 or 1-0 game is not as clear-cut. For example, he found that for 2-1 matches almost one-third of the time the better team does not win.

That uncertainty influences the entire tournament. Skinner said that the first round of the World Cup will likely identify the better teams because each team plays each of the other three teams in the group. But the following rounds are single elimination, and the uncertainties of the outcomes of four successive games add up. Skinner found that the likelihood that the best team would win the World Cup is around 28 percent.