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Do helmets make sports more violent?

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This week Decision Science News and Peter McGraw’s blog team up for a joint post. — Enjoy

The New York Times just ran a piece called “A Case Against Helmets in Lacrosse“.

The hook of the article is that wearing helmets, which one would expect to make the game safer, could make the game more dangerous. Let’s review the quotes.


It’s hard to absolutely prove, but what we’ve seen is that behavior can change when athletes feel more protected, especially when it comes to the head and helmets,” said Dr. Margot Putukian, Princeton’s director of athletic medicine services and chairwoman of > the U.S. Lacrosse safety committee. “They tend to put their bodies and heads in danger that they wouldn’t without the protection. And they aren’t as protected as they might think.”


Then again, other sports have spent the last several years realizing that safety equipment can bring dangers of its own. Checking in professional hockey became considerably more vicious with the adoption of helmets in the 1970s and ’80s, and football players felt so protected by their helmets and face masks that head-to-head collisions became commonplace at every age level.

Three (re: protective eyewear in Women’sLacrosse):

[Someone] said that after the move to make eyewear mandatory for the 2005 season, “It’s subconscious, but you see harder checking, and rougher play.”

Interesting topic! Let’s get Dan and Peter’s take on it:

This is an example of moral hazard, which the Wikipedia (at least during the last five minutes) defines as a situation in which “a party insulated from risk behaves differently than it would behave if it were fully exposed to the risk.” The top 10 Google Scholar papers with “moral hazard” in the title have over 10,000 collective citations. You hear a lot about moral hazards, for example, that people began driving more recklessly when seat belts were invented, at cocktail parties, coffee breaks, dinners with visiting speakers, and other moments in which people say what they really think.

Is it possible that requiring lacrosse players to wear helmets will increase risk to players? I doubt it. My grounds for skepticism? TCTBT: too cute to be true.

TCTBT (also “too clever to be true”) arguments survive not because they are correct, or supported by the best evidence, but because they are elegant, counter-intuitive, and make a person sound smart at a cocktail party. They fly well in Op-Ed pieces, keynote speeches, and other places where one is unlikely to be asked for evidence.

The smart thing to do when you hear a TCTBT explanation is to doubt it. Since repeating a clever explanation is clearly its own reward, how is one to say that the person offering it is well-informed or just trying to be conversationally brilliant?

While I feel that moral hazard is overhyped, I must admit that I’ve gone spelunking with a helmet and without a helmet, and yes, a person does let his head bump against the cave walls more often with the helmet on than off. However, the net impact to your head is less with the helmet on. This is what I would expect to happen in lacrosse. More helmets will bump against helmets, which seems more ‘violent’, but the net noggin impact will be less. And despite popular belief, they have rules in lacrosse, so the temptation to run helmet first into people may not even have an advantage.

Interestingly, the article says, “checking in professional hockey became considerably more vicious with the adoption of helmets in the 1970s and ’80s”. Again, correlation, is not causation. And is ‘viciousness’ measured in injuries?

I say let Moral Hazards join Prisoner’s Dilemmas, Tragedies of the Commons, and other cleverly constructed scenarios that don’t arise in proportion to the vast numbers of articles written about them. Pay more attention to boring things like default effects that exert large and demonstrable influences on hundreds of decisions in daily life.

That said, I know nothing about lacrosse except that I watched Pete play it once, so without further ado, I’ll turn the typing over to him. If you have empirical evidence of moral hazards we should be concerned about, please post in the comments.

As someone with more than 30 years of (combined) lacrosse coaching and playing experience, my intuition leads me to believe that introducing helmets into the women’s game will increase the behaviors that put players at risk of injury. However, given that I regularly lecture on the fallibility of intuition, I also agree with Dan. I would like to see causal evidence before drawing a line in the sand. More important than just examining if helmets increase risky behavior, the analysis for deciding to institute helmets would need to balance the costs of the risky behavior against the benefits of the helmet. That is, the temporary bumps and bruises caused by more aggressive play may be worth incurring in order to reduce the risk of concussion. In that way, a thorough risk analysis would seem to be worth the price given the many thousands of women and girls who play the game.

The question of wearing a helmet creates a moral hazard in the game of lacrosse is complicated because the presence of the helmet would seem to influence more than just the offensive and defensive player’s behavior. The protection that a helmet provides could influence the way that the official monitors the game. Officials could more laxly (no pun intended) enforce the rules because they perceive the aggressive behavior as less risky, which in turn could further increase aggressiveness.

One last way to think about the helmet debate is to consider how much the debate is being colored by tradition (aka the status quo). And in this way, a useful question would be, if a new sport like lacrosse was created, would helmets be required given the emerging evidence about the risks of concussion?

Photo credit:http://www.flickr.com/photos/timailius/2472012607


  1. Tweets that mention Do helments make sports more violent? | Decision Science News -- Topsy.com says:

    […] This post was mentioned on Twitter by Zeynep Arsel, Dan Goldstein. Dan Goldstein said: Do helmets make sports more violent? http://goo.gl/fb/a8GLB […]

    February 23, 2011 @ 11:43 am

  2. Daniel Reeves says:

    I don’t like the application of “moral hazard” here. “Hazard”, yes. “Moral”, no. To constitute “moral hazard” you should be inflicting cost on others because you in particular are shielded from the risk of your actions. According to wikipedia, moral hazard is a special case of information asymmetry. With lacrosse players it’s all quite symmetric. I would just call it compensating behavior. That’s what I’ve heard it called in the context of seatbelts and airbags and antilock brakes. There’s a certain level of risk people feel comfortable with and so safety equipment that lowers that risk allows people to drive more aggressively. (Imagine how you would drive with no seatbelt and a spear coming out of the steering wheel pointing at your neck.)

    Still, I agree that it’s TCTBT that compensating behavior would always perfectly cancel out the benefits of safety equipment, or that people would overcompensate.

    February 23, 2011 @ 12:19 pm

  3. dan says:

    Danny – Ha ha, the spear at the chest line is the kind of example used by TCTBT raconteurs. In fact, I have heard that exact analogy made by a swaggering economist, speaking to an enrapt group, at a coffee break in an academic research institute. Yet, within the bounds of devices that people actually invent and adopt (i.e., spears at the chest aside), my bet is that people basically drive as if they weren’t wearing seat belts. Cute concept, little relation to behavior.

    As to seat belts being a purported moral hazard, my internet searches suggest I am not alone in this categorization. As to it being quite symmetric, note that college football prohibits spearing, defined as “the deliberate and malicious use of the head and helmet in an attempt to punish a runner after his momentum has been stopped.” Reference.

    The separate uses of derivations of the word spear in this comment are unintentional.

    February 23, 2011 @ 1:11 pm

  4. Mike says:

    Moral Hazard has been shown to make a huge difference (statistically, with lots of evidence, NOT just at cocktail parties) in a lot of real-world markets. Insurance is a great example. I worked on a project for a large health insurance firm and we found that after controlling for the fact that riskier individuals take larger insurance plans, those with larger plans engaged in riskier behavior and made more claims. You should read all those papers with thousands of citations, and lots more; you’ll find lots of examples of real-world moral hazard.

    I don’t think Moral Hazard is a counter-intuitive or clever argument at all, it is rather straightforward: those with more insurance act riskier, meaning those who bear less of the cost of risk engage in more risk. This is incredibly intuitive. I see all the time in lacrosse that girls are whacking the other players in the head and helmet; something I’ve never seen for men’s lacrosse.

    But I agree with you that we can’t just say a priori that people will be safer without helmets; that claim would need a lot of support (although evidence is starting to mount in that direction for ncaa football). And although I would not put moral hazard in the “TCTBT” category, it is starting to get to the point that most publications in marketing, psychology, and economics have that TCTBT flavor; that is why they are read and get the talk, because they are counter-intuitive and provocative, no one would give props to a study that shows up that what we expect to happens actually happens, and so we are biased towards the studies that give us the most extraordinary results, but that are least likely to apply generally.

    March 6, 2011 @ 8:21 pm

  5. dan says:

    Hi Mike,

    Nicely written comment!

    If you or anyone knows of a field experiment showing that people randomly assigned to insurance policies increase their risk of harming others, please let me know about it.

    March 9, 2011 @ 10:16 pm

  6. Maria says:

    ” This is incredibly intuitive. I see all the time in lacrosse that girls are whacking the other players in the head and helmet; something I’ve never seen for men’s lacrosse. ”

    Did you intend the reverse? Because it doesn’t make any sense as a discussion of moral hazard. Indeed, it would prove the opposite.

    I wonder how moral hazards ebb and flow over time? For example, with safety equipment do people for a time take more risks and then, upon either learning that they are not properly insulated or some other negative repercussion (ie, a traffic ticket or a yellow card) does it tail off?

    June 27, 2011 @ 10:56 am

  7. Andy says:

    Nice article!

    There is a big discussion going on about something in the same category: bicycle helmets. Worth having a look here:


    July 20, 2011 @ 1:33 am

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