A match played in a sports tournament can be called stakeless if at least one team is indifferent to its outcome because it already has qualified or has been eliminated. Such a game threatens fairness since teams may not exert full effort without incentives. This paper suggests a novel classification for stakeless matches based on their expected outcome: they are more costly if the indifferent team is more likely to win by playing honestly. Our approach is illustrated with the 2026 FIFA World Cup, the first edition of the competition with 48 teams. We propose a novel format based on imbalanced groups, which substantially reduces the probability of stakeless matches played by the strongest teams according to Monte Carlo simulations. The new design also increases the uncertainty of match outcomes and requires fewer matches. Governing bodies in sports are encouraged to consider our innovative idea in order to enhance the competitiveness of their tournaments.

翻译：在体育赛事中，若至少一方队伍因已晋级或淘汰而对比赛结果无动于衷，则该场比赛可称为'无利害关系比赛'。此类比赛可能威胁公平性，因为队伍在缺乏激励时未必全力以赴。本文提出一种基于预期结果的无利害关系比赛新分类：若漠不关心的队伍通过正常发挥更可能获胜，则比赛代价更高。我们以2026年国际足联世界杯（该赛事首次扩充至48支队伍）为例，阐释了该方法。基于蒙特卡洛模拟，我们提出一种基于不平衡分组的新赛制，能显著降低强队参与无利害关系比赛的概率。新设计同时增加了比赛结果的不确定性，并减少了总比赛场次。建议体育管理机构考虑这一创新方案，以提升赛事竞争力。