Tuesday, June 17, 2014

Should We Have Expected John Brooks’ Goal?

Yesterday in a thrilling match, US defender John Brooks scored in the 86th minute to secure a win over for the Americans over Ghana. The goal came off of a corner kick delivered by Graham Zusi. An exciting play for sure and a critical 3 points for the US. But, at this point in the World Cup competition should we have expected a goal to come from a corner kick?

In the 2010 World Cup, 627 corners were taken that resulted in 9 goals. That’s an average of one goal scored for every 70 corners attempted. Graham Zusi’s was the 126th corner taken so far in this year’s competition. Prior to the US goal, Switzerland and German scored the only goals from corner kicks. Add the US goal and we have 3 goals scored from 127 corners (Ghana had one CK after the US goal). That’s an average of 1 goal every 42.3 attempts. Slightly less than the 2010 average.

Based on the 2010 statistics, should we have expected the US to score? The average so far is about nine corner kicks per match so the next corner kick goal should have come about three matches later, not in this match. Given that stat, should the US have played a short corner and kept possession? Obviously not! They clearly made the right call. All statistics have some degree of randomness, outliers that occur outside of what is expected. And this is what makes the game so exciting – goals coming at unexpected times from unexpected players. In this case, John Brooks and Graham Zusi created their own outlier - an unexpected goal that earned the US the win.