A new competition format to avoid collusion in three-team sports tournaments

Abstract: The usual FIFA World Cup-TM group stage format is eight groups of four teams for a total of 32 teams. The top two teams from each group advance to the next round, resulting in a 16-team knockout stage. The next edition of the World Cup will have 48 teams. Although FIFA initially proposed a configuration of 16 three-team groups, it has ultimately settled on 12 four-team groups. The format chosen, based on four-team groups, has clear organizational disadvantages and even a lack of fairness in the competition. But, in return, there is less risk of collusion in groups of four teams than in groups of three teams. This study proposes a modification to the three-team group format to reduce the risk of collusion by making the order of the matches not predefined in advance. The results obtained with Monte Carlo simulations show that the new three-team competition format with dynamic match order is comparable, in terms of collusion risk, to the four-team group system commonly used in past World Cups.