It’s one of those things that make soccer such an intense and nail-biting sport — penalty shootout. But are penalty kicks actually fair and how likely is it that the goalie can successfully block a penalty kick? With the help of statistics and economist, Ignacio Palacios-Huerta, who studied more than 11,000 penalty kicks, we take a look at why penalty shootouts are so unfair to the goalies and what can be done about it. Following is a transcript of the video.
Narrator: 0.4 seconds. That’s the time it takes you to blink. It’s also about how long goalkeepers have to save a penalty kick or fail trying. And it’s certainly not enough time for a goalie to react and respond. So goalies can’t solely rely on their speed and agility to save a penalty kick. Instead they have to pretty much guess which direction to go and rely on either luck or game theory.
Game theory is a popular strategy in economics where the outcome of a situation relies more on how well you predict your opponent’s actions than how you perform your own. So since the goalie has no choice but to guess, they’re better off guessing logically than randomly. That’s where economists come in.
Ignacio Palacios-Huerta: I would like to know what you do in the last 80 penalty kicks you faced? Do you have any tendencies? What does this guy do against right-footed kickers versus left-footed kickers?
Narrator: That’s economist Ignacio Palacios-Huerta. He studied over 11,000 penalty kicks, and in 2008 during the UEFA Champions League Final, it paid off, sort of. It was Manchester United against Chelsea. The game came down to a penalty shootout which was the perfect opportunity for Chelsea to put Huerta’s advice into action.
Along with several pointers Huerta had given Chelsea’s goalie a key insight about Manchester United star Cristiano Ronaldo. Ronaldo would almost certainly kick the ball to the right if he paused on the run-up. And the advice worked. Ronaldo indeed paused and indeed kicked the ball to the right. Chelsea’s goalie followed Huerta’s advice and made the save. Ultimately Manchester United won the game, but despite Chelsea’s loss, it was clear that economists and statisticians can help even the odds when it comes to penalty kicks.
Because otherwise, it’s a crap shoot for the goalie. In 2014 for example, FiveThirtyEight calculated that 72.5% of penalties in World Cup history went in. For all competitions worldwide, it’s even higher. And when you take a closer look, it’s no wonder. Human response time takes roughly 1/10 of a second to kick in. The average kicker kicks a 70 mile per hour ball, which means the goalie won’t even register the ball’s direction until it’s about 25 feet away. It will take him another .5 to .7 seconds to react and reach for the ball, but by that point, it’s all over.
Now the goalie can improve the odds if they start to move before the ball is even kicked, but the goalie still has to basically guess a side and just go for it. So if time is the goalie’s enemy, maybe we should just move the penalty kicker further back. But for now, economists are a goalie’s best friend when it comes to stopping penalty kicks, and turns out, Huerta is helping a team in the 2018 World Cup, though he wouldn’t tell us who.
from SAI https://read.bi/2MYdxVH