Designing practical and fair sequential team contests: The case of penalty shootouts

Abstract

Economists have long recognized that the effect of move order on outcomes is non-negligible in sequential contests. We study tiebreak mechanisms used in team sports and known as penalty shootouts through a dynamic model. We characterize all order-independent mechanisms where two balanced teams have equal chances to win the shootout whenever they are tied after equal numbers of attempts; thus, move order has no relevance for winning chances. In most sports, such as football and hockey, teams take penalties in a fixed order, known as ABAB, while some tournaments adopted the alternating-order variant, ABBA. We find that these and all other exogenous-order mechanisms – with one exception – are order-dependent in regular rounds. Although ABBA is order independent in sudden-death rounds, ABAB is not. Our theory supports empirical studies linking ABAB to unfair outcomes and multiple equilibria in terms of winning chances of the first- vs. second-kicking teams in different football traditions.