Cognitive Daily

Penalty kicks are nearly universally reviled among soccer fans, yet they remain an important part of the game. The sport is so exhausting that extending it beyond 30 minutes of extra time in a playoff game could be dangerous for the players. Typically in playoff or championship matches, tie games get decided by a penalty kick competition.

But penalty kicks offer such an advantage to the shooter that it often seems like dumb luck when a goalkeeper manages to make a save. The usual strategy is simply to dive randomly to the left or right, and hope you guessed right. Why not just flip a coin to decide who wins the match? Chris at Mixing Memory has found a study suggesting that the position of the goalkeeper just before the shot can indeed affect the shooter:

They found that in almost all instances (96%), the goalkeeper stood just slightly (and I mean just slightly) off center, creating a difference between the distance of the goalie from the two goal posts of about 9.95 centimeters, which amounts to a difference between the areas to the right and left of the goal keeper of about 2.9% of the total area of the goal. The side to which the goalie stood did not, however, influence the side to which the goalie dove as the ball was kicked. So goalies didn’t seem to be aware of their position. However, when they looked at whether penalty takers were aware of the position of the goal keeper, they found that 103 out of 174 (I’m not sure what happened to the other 26 kicks) were to the side of the goal keeper with more space. So the position of the goal keeper does appear to affect the direction of the kick on a (statistically) significant percentage of penalty kicks. Penalty takers are, then, aware of the goalie’s position.

200 kicks were studied, and 103 out of 174 went to the side with the most space between the keeper and the post. (What happened to the other 26 kicks? I’d guess they were straight at the keeper.) A separate series of experiments confirmed these results: though neither kicker nor keeper is aware that the keeper could be biased by as much as 3 percent to one side, more kicks went toward the side with more space.

The researchers suggest that keepers could use this subtle advantage to influence the direction of kicks, but Chris begs to differ:

Yeah, a lot of good that knowledge does us. If we were soccer coaches, and wanted to use this research, we’d quickly find that it wouldn’t help us a bit. Kickers are obviously already utilizing their ability to detect to which side of center the goalie is standing, and goalies seem to be unable to notice their position relative to the center, so they can’t use it to decide in which direction they should dive. ut hey, some psychologists got to watch a bunch of penalty kick videos, and I got to write a post about it, so it’s not a complete waste.

I’m not sure I buy that argument. Perhaps through extended experimentation, psychologists could devise a method by which goalkeepers could recognize the direction in which they are biased, thus gaining an advantage! Of course, such a project would require watching even more soccer games….

Comments

#1 Pele
April 24, 2007

Hmm, maybe if your strategy would be to position yourself, move 10cm to one side and dive the other way, it would work for a while. Until the shooter could learn that you are telegraphing your plan by an obvious shift, or are aware of you’re positioning.
#2 Akshaye
April 24, 2007

I’m not sure if I can agree with the goalies not knowing their position. Can’t an experienced goalie tell where he’s standing relative to the position of the ball? Or is the ball too far to notice any small deviations?
#3 Dave Munger
April 24, 2007

Well, we’re only talking about 8 or 9 centimeters — 4 inches, compared to a 24 foot goal width.

But a goalie could precisely measure the goal before the game and put an inconspicuous mark on the ground to help align himself…
#4 Matthew
April 24, 2007

Not sure I buy the whole “keepers not aware of there position” aspect. I’ve been a goalkeeper for nearly 12 years and I learned early on(say 2-3 years of playing) to make a small indentation at the center of each goal line. Usually I place this about a yard in front of the goal line, thus allowing me to see it before a penalty is taken. Also an area not included is how a shooter is affected by a goalkeeper that moves side-to-side, along the goal line, prior to the shot. This action often dictates which side of the goal a shooter will shoot towards and can be beneficial to goalkeepers as they can (seemingly) expose their stronger (or preferred) side to dive towards. It’s worked for me in every area from house-league up to provincial(rep. league)
#5 Karl
April 24, 2007

Since, as you say, they don’t want to go beyond 30 minutes of extra time, here are two suggestions for how to reduce the possibility of a tie.
1) If I am correct, with a tie each side gets 1 point in the standings, rather than the 2 for a win. Give 0 points to each side in a tie. This increases the benefit of a win without reducing the penalty for a loss – greater incentive to open up, attack more, rather than go into a shell and play for the 1 point tie.
2) Copy the technique that the National Hockey League uses. Reduce the number of players on each side. At the beginning of overtime reduce by 1, after 5 minutes reduce 1 (or maybe 2) more players, after 5 more minutes reduce 2 (or maybe 3) more players. Fewer players, more open space, greater chance of scoring.
#6 Matthew
April 24, 2007

Karl you’re a bit confused as to points awarded. it’s 3 for a win, 1 for a draw (tie), and 0 for a loss. However extra-time in soccer isn’t an everyday occurrence, only happens when 1 team has to move forward in a competition, think knock-out competition such as quarter-, semi- and finals.
#7 Karl
April 24, 2007

Matthew: That’s irrelevant. You can still make it 3 for a win and 0 for a tie, even more incentive to go for the win. The point is that awarding even 1 point for a tie puts teams into total defensive mode and eliminates aggressive play. Also, the discussion is about shoot-outs being a bad way to break a tie. If you are not now trying to break ties, then don’t use it there. I’m giving a better way to break ties in those cases where it must be done.
You didn’t comment on my other proposal. What do you thing about reducing the number of players as a method for doing it?
#8 Matthew
April 25, 2007

I personally prefer the shoot-out, both as a player and as a fan. As a player it gives the feeling of an “all on the line” type play. And considering it’s a best of 5 shots the pressure is completely on the shooters rather than the keeper. A keeper is likely to stop 1 in 10 penalty kicks so really the fact that most sudden-death shoot-outs only last the 5 shots is more a lack of concentration on the player taking the kick than the keeper being in a better position.
#9 John
April 25, 2007

This is more a comment about penalties themselves rather than the main focus of the text. I’m not too sure I would consider penalties to be “nearly universally reviled” – I think they can be a heart-stopping way of finishing a game.

I remember a few years ago my team were competing in the UEFA Cup and the game went to penalties. It was so unbelievably tense, but there was such a rush of relief and pleasure at the end when my team went through. My team’s also been on the losing side to penalties, so I know all about how horrible it is to lose that way, but I still think it’s a great and fair way to end a game.

I also think that there’s a fair amount of skill involved – some of the penalties scored in the European leagues can be very creative – by this I mean the striker can fool the goalkeeper using their body posture before kicking the ball.
#10 Jongpil Yun
April 26, 2007

Karl’s idea sounds like it could work.
#11 Steve
April 27, 2007

As a goalkeeper I used to “cheat” to one side or the other on penalty kicks, and it worked very well. The strategy was even more successful on an indoor field, where the goal is smaller and it is harder for the shooter to place his shot outside the keeper’s reach while still inside the frame. The shooter was more apt to fall for the perceived advantage.

If the strategy became stale through overuse, slightly turning feet and hips, and shifting weight could usually convince a shooter that they knew which way you intended to move.
#12 doug
April 28, 2007

There is also the subject of players’ preferences.

http://www.all-encompassingly.com/jens-lehmann-to-auction-the-note/
#13 christopher
May 17, 2007

funny, as a player i never thought about where the goalie was. id have to agree with matthew – players not scoring is probably more about their concentration. i used to be the shooter for my team and the only penalty kick i ever missed i shot over the goal.

the only reason i feel the shootout is unfair is because if a player places the ball the correctly it really doesn’t matter how well or in which direction a goalie dives.