Engineering professor Luís Amaral has investigated complex social and structural networks in areas ranging from healthcare and biology to gender discrimination and gun violence. His diverse research interests and innate curiosity eventually led him to study soccer — his favorite sport.

Amaral used his knowledge of network complexity to create an algorithm that objectively ranks professional soccer players. With the help of students in his lab, Amaral built a network for each team, which reflected who passed the ball to whom, how accurate those passes were, and how likely those passes were to end in a goal.

Before Amaral’s algorithm, the only way to identify stellar soccer players was by listening to sports pundits. Amaral’s lab developed the first objective, data-driven system for understanding who to watch on soccer fields across the globe.

Using sophisticated coding techniques and analytical tools, Amaral’s team created what they termed an “Average Footballer Rating” (AFR) for each player, based on how influential they are in soccer matches. Taken together, the AFR values of all players on a given team indicate that team’s strength — its success at making passes that result in goals. For people who follow soccer, the top three players – Lionel Messi, Neymar Jr., Cristiano Ronaldo — are no surprise.

“A player with an AFR greater than 70 is pretty much superhuman,” Amaral says. “And an AFR above 70 over many seasons is god-like.”