Games played in the final round of a round-robin contest may inspire collusion and match-fixing if there exists a result allowing both teams to advance. Our paper reveals that using head-to-head records as the primary tie-breaking principle might lead to such situations. We identify all possible cases in a single round-robin tournament with four teams. According to simulations based on the UEFA European Football Championship, merely the misaligned tie-breaking policy increases by about 12 percentage points the probability of a match with a collusion opportunity. The danger can scarcely be mitigated using a static match schedule.

翻译：在循环赛制的最后一轮比赛中，若存在使两队均可晋级的结果，可能诱发共谋与假球行为。本文揭示以直接交锋记录作为首要平局决胜原则易导致此类情形。我们识别了四队单循环赛制中的所有可能情形。基于欧足联欧洲足球锦标赛的模拟显示，仅因平局决胜规则的不协调，便使存在共谋机会的比赛概率提升约12个百分点。采用固定赛程表几乎无法缓解这一风险。