Winning by Losing

2020

Ann Oper Res

Fairness has several interpretations in sports, one of them being that the rules should guarantee incentive compatibility, namely, a team cannot be worse off due to better results in any feasible scenario. The current seeding regime of the most prestigious annual European club football tournament, the UEFA (Union of European Football Associations) Champions League, is shown to violate this requirement since the 2015/16 season. In particular, if the titleholder qualifies for the first pot by being a champion in a high-ranked league, its slot is given to a team from a lower-ranked association, which can harm a top club from the domestic championship of the titleholder. However, filling all vacancies through the national leagues excludes the presence of perverse incentives. UEFA is encouraged to introduce this policy from the 2021-24 cycle onwards.

Section: Related Literaturementioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

The UEFA Champions League seeding is not strategy-proof since the 2015/16 season

2020

Ann Oper Res

“…Consequently, the axiomatic approach can be fruitful in the choice of an appropriate sports ranking method. This issue has been discussed in some recent works (Berker, 2014;Pauly, 2014;Csató, 2017Csató, , 2018aDagaev and Sonin, 2017;Vaziri et al, 2018;Vong, 2017), but there is a great scope for future research.…”

Section: Introductionmentioning

confidence: 99%

Some Impossibilities of Ranking in Generalized Tournaments

2019

Int. Game Theory Rev.

In a generalized tournament, players may have an arbitrary number of matches against each other and the outcome of the games is measured on a cardinal scale with a lower and upper bound. An axiomatic approach is applied to the problem of ranking the competitors. Self-consistency requires assigning the same rank for players with equivalent results, while a player showing an obviously better performance than another should be ranked strictly higher. According to order preservation, if two players have the same pairwise ranking in two tournaments where the same players have played the same number of matches, then their pairwise ranking is not allowed to change in the aggregated tournament. We reveal that these two properties cannot be satisfied simultaneously on this universal domain. JEL classification number: C44, D71MSC class: 91A80, 91B141 The term order preservation may be a bit misleading since it can suggest that the sequence of matches does not influence the rankings (see Vaziri et al. (2018, Property III)). This requirement obviously holds in our setting.

“…Here we do not deal with this probabilistic aspect of manipulation, it is assumed that a team deliberately loses only if it cannot be worse off by tanking, in other words, teams are extremely risk-averse in the choice of their strategy. Examples include a famous football 2 match played by Barbados and Grenada in the 1994 Caribbean Cup qualification (Kendall and Lenten, 2017, Section 3.9.4), qualifications for FIFA Worlds Cups (Dagaev and Sonin, 2013;Csató, 2017), UEFA club competitions (Dagaev and Sonin, 2017;Csató, 2018c,e), UEFA European Championships (Csató, 2018a,d), or tournaments with subsequent group stages (Csató, 2018b).…”

Section: Introductionmentioning

confidence: 99%

When neither team wants to win: A flaw of recent UEFA qualification rules

International Journal of Sports Science & Coaching

2020

Tanking, the act of deliberately dropping points or losing a game in order to gain some other advantage, is usually seen as being against the spirit of sports. It can be even more serious if playing a draw is a (weakly) dominant strategy for both teams in a match, since this may lead to collusion. We show that such a situation occurred in a particular football match. As our generalisation reveals, the root of the problem resides in the incentive incompatibility of certain UEFA qualification rules. The governing bodies of major sports should choose strategy-proof tournament designs because of several reasons. First, they may lead to the elimination of a third, innocent team. Second, incentive incompatible rules may discourage both teams from scoring goals, and the players could be interested in improving other match statistics than the number of goals.