Penalty shoot-outs are basically still crap-shoots

Penalty shoot-outs are basically still crap-shoots

IN 1978 the World Cup scrapped its policy of choosing the winner of knockout-stage matches tied after 120 minutes with a coin flip, and introduced penalty shoot-outs to replace them. The idea was to have a result determined quickly, using a method that at least partly depended on skill. However, the evidence that shoot-outs actually favour the stronger team is extremely thin: sides with more impressive won-lost records and goal differentials (after accounting for the quality of their opposition) do not win an outsize share of shoot-outs against weaker rivals.

Ironically, the best predictor of success in shoot-outs is still a coin flip. The contests begin with one, to determine which team gets to choose whether to go first or second. And kicking first seems to convey a hefty advantage. According to a study by Ignacio Palacios-Huerta of the London School of Economics, sides that go first under the current A-B-A-B shooting sequence win 60% of the time.

Kickers and goalkeepers have broadly settled into an equilibrium regarding the direction of the ball (left, centre or right). Shooters can generally kick the ball harder when aiming for the opposite side of the goal from their strong foot. As a result, they tend to fire this way around 25% more often than they do in the other direction. Goalkeepers, however, are well aware of these preferences, and dive in each direction in matching proportions. As a result, success rates on all kick directions are similar.

One potential inefficiency revealed by the data is the height of the kick. Goalkeepers find high balls the hardest to deal with—just 3% of penalties aimed halfway up the goal or more are saved. Such attempts are risky: 18% of high shots miss their target, as opposed to 5% of low shots. Overall, though, allowing for misses and saves, high shots are successful 79% of the time compared with 72% for low ones (see chart).

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