Most penalty kicks result in a goal; this is why soccer players go to such comical lengths to draw a penalty. The distance between the ball and the goal is so short that goaltenders don't have time to react; they have to commit to a strategy as the ball is being kicked. The usual strategy is to try and guess where the ball will be kicked and to jump in that direction. Surprisingly enough, the tactic of not jumping - that is, guessing that the ball will be kicked down the middle - is under-utilised.
An interesting study from a group of Israeli researchers (Bar-Eli et al, 2007) offers a plausible explanation: 'action bias'.
Jump direction | |||||
---|---|---|---|---|---|
Left | Center | Right | Total | ||
Kick direction | Left | 0.189 | 0.003 | 0.129 | 0.322 |
Center | 0.143 | 0.035 | 0.108 | 0.287 | |
Right | 0.161 | 0.024 | 0.206 | 0.392 | |
Total | 0.493 | 0.063 | 0.444 | 1.000 |
Goaltenders jumped in more than 90% penalty kicks in the sample: the frequency of staying put was only 6.3%. Kickers, on the other hand, distributed their targets in roughly equal proportions.
The goaltenders' strategy was not wholly ineffective: when the kicker aimed left or right (71.4% of the time), goaltenders guessed correctly 6 times out of 11. But the fact remains that the frequency of the goaltender staying put (6.3%) is much smaller that the frequency of kicks aimed down the middle (28.7%).
This under-reprentation is even more puzzling when you look at the save percentages. This is a reproduction of Table 2:
Jump direction | |||||
---|---|---|---|---|---|
Left | Center | Right | Overall | ||
Kick direction | Left | 0.296 | 0.000 | 0.000 | 0.174 |
Center | 0.098 | 0.600 | 0.032 | 0.134 | |
Right | 0.000 | 0.000 | 0.254 | 0.134 | |
Overall | 0.142 | 0.333 | 0.126 | 0.147 |
Unsurprisingly, when kickers aim left or right, goaltenders never stop the ball when they guess wrong before jumping. What may be surprising is that even when they jump in the correct direction, the save percentage is less than 30%. On the other hand, on the rare occasions in which goaltenders (correctly) stay put, the save percentage is 60%.
To summarise:
- The frequency with which goaltenders stay in the centre of the goal is much lower than the frequency with which kickers aim for the centre.
- Correctly staying in the centre has a much higher save percentage than jumping in the correct direction.
This doesn't mean that goaltenders should never jump. What it does mean is that goaltenders jump far too often. Why?
Bar-Eli et al suggest an explanation: 'action bias'. This is presented as an example of Kahneman and Miller's (1986) 'norm bias'. Goaltenders believe it is less bad to follow the 'norm' (i.e., to jump) and fail than to not jump and fail. In other words, goaltender think that jumping and missing is less costly than not jumping and missing.
Which brings us to economic policy. Politicians are continually demanded to 'do something' about a kaleidoscopic array of grievances, and the norm in these cases is to promise to do something. As far as politicians and most voters are concerned, doing something is better than doing nothing - even when doing nothing is the correct response.
In many cases - possibly the majority of cases - doing nothing is the smart move. A recent example is the concern about the so-called 'skill shortage'. When firms complain that they can't get the workers they want at the wages they are willing to pay, the correct response is to do nothing: the market response to a labour shortage is to let wages increase.
But doing nothing is almost always bad politics: it is invariably interpreted as a lack of concern, and this percieved indifference will be pounced upon by other political parties. A politician who promises to act polls better than one who promises to do nothing.
Goaltenders jump because jumping is expected of them: they fear to look silly by not jumping, even if not jumping is the smart move.
Politicians promise action because action is expected of them: they fear to look uncaring by not acting, even if inaction is the smart move.
Note: I started writing this *before* Nick's post about the macroeconomics of 'doing nothing'. Really!
Damn! And I was just thinking about another post on "doing nothing", saying it could mean anything. And yet in your examples, "doing nothing" does seem to mean something (it has a plausible natural interpretation)!
BTW, there's a good comment stuck in spam.
Posted by: Nick Rowe | May 22, 2014 at 07:42 AM
OK, the political interpretation seems plausible enough, but I am not so sure about that "natural interpretation".
There does not seem to be any reason why kickers should ever decide in advance to aim for the centre. The chance of success, conditioned on the goaltender guessing right, is higher for the corners than for the centre. And the chance of success, conditioned on the goaltender guessing wrong, is also higher.
There is an entirely different plausible natural interpretation than "action bias". Perhaps kickers (almost) always intend in advance to kick for one corner or another - that would be rational. Goaltenders seem to be able to divine the kicker's intention better than chance, as you yourself observed (by 189/129 left and 206/161 right.) If they are sometimes anticipating the kicker's choice, perhaps they sometimes do so prematurely, so that the kicker has time to change the course of the kick. It might well be that it is physically easier to redirect a kick to the centre than to the opposite corner; that would explain the high incidence of centre kicks.
But in that case, it would not help the goaltender to increase the frequency of standing pat; the kicker would just continue his original plan and kick to a corner, and there would be no save.
Posted by: Phil Koop | May 22, 2014 at 10:43 AM
Great post, really like it. Course one could always try to look like you're doing something, like jump up and down impressively while staying in the middle of the goal, and not actually do anything at all.
Posted by: Frances Woolley | May 22, 2014 at 12:24 PM
There is a "skill shortage". Let the wages rise (ok). With these higher wage, some people will "increase their skills". Which the same thing as "increasing skills" immediately, but taking more time. Then , what's wrong about "doing something about skills"?.
Posted by: Jacques René Giguère | May 22, 2014 at 07:29 PM
The choice here is really identification of the problem, not action to solve the problem. It's silly to worry about a skills shortage (a small fish problem) when the labour market can't clear anyway EVEN IF there was no skills shortage (a big fish problem).
http://www.statcan.gc.ca/daily-quotidien/140318/dq140318b-eng.htm
This says "involuntary unemployment" to me. We don't have a skills shortage, we don't have enough jobs. But the solutions to this problem are politically unpalatable to many.
Posted by: Determinant | May 22, 2014 at 11:13 PM
Frances: I coach football, uh, soccer. The goalie is not permitted to jump around prior to the ball being kicked. FIFA Law 14 states "(The goalie) must remain on his goal line, facing the kicker, between the goalposts until the ball has been kicked"
http://www.fifa.com/aboutfifa/footballdevelopment/technicalsupport/refereeing/laws-of-the-game/law/newsid=1290872.html
Posted by: Patrick | May 23, 2014 at 01:24 AM
Most soccer goalies, especially at the higher levels, do a little more than randomly jumping - they usually base it on past data, and the way the other player is running up to the ball. Also, with the goalie standing in the center I wonder how many players actually aim at the middle. I think the statistical data is hiding a lot of variables inherent to the problem.
Having said that, even if action bias is valid, how do you pre-determine that a specific problem susceptible to action bias, and that no action is best? Is there some type of groundwork that can be done to evaluate a situation?
Posted by: Gratuz | May 23, 2014 at 09:04 AM
This problem is made even worse when there is an option value in waiting. Not only does the politician feel compelled to act, he/she feels compelled to act now, often when the decision is irreversible (or difficult to unwind). Every time we see politicians trying to pull investment forward, whether it be rebates for clunkers or what not, politicians fail to recognize the socially optimal action of delay. For young economists reading this blog post, read Dixit and Pindyck's excellent text, Investment Under Uncertainty.
Posted by: Avon Barksdale | May 23, 2014 at 07:58 PM
You correctly anticipated where I was going to go next with this line of thought!
Posted by: Stephen Gordon | May 24, 2014 at 08:50 AM
Here's the type of action bias I see too much of: when action is important, if not critical, then do nothing. (Ie. global warming, where the longer we wait, the harder it is to slow down let alone stop or reverse.) On the other hand, if there's no real problem, WE MUST ACT FAST! (Social Security is precious for the future. We must save it by cutting benefits now! Earlier, it was privatize it! Earlier still, it was Social Security is bad.)
Posted by: John H. Morrison | May 24, 2014 at 08:57 AM