Tournament Design for a FIFA World Cup with 12 Four-Team Groups: Every Win Matters

After the expansion of the FIFA World Cup from 32 to 48 teams starting in the 2026 edition, the initial proposal was to split the 48 national teams into 16 groups of three. Among other drawbacks, this proposal provides potential for collusion. Recently, after widespread criticism, FIFA officials decided to revisit that proposal, instead approving a tournament with 12 groups of four teams. However, the approved format does not eliminate the possibility of collusion. In this chapter, we propose tournament formats for a World Cup with 12 groups of four teams, considering several criteria, such as non-collusion, symmetry in rest days, and no dead rubbers. At the same time, our proposals attempt to adhere to the traditional format, with some nuances in either the group or elimination stage.