Sunday, July 02, 2006

Tradeoffs: Wearing helmets

Every media discussion I have read or seen assumes that helmets save lives. I have yet to see the discussants present any evidence that warrants this conclusion, nor consider any of the tradeoffs that might make it sensible for some cyclists not to wear helmets.

A while ago, the Miami Herald ran an editorial noting the lives saved by helmets. The reasoning was based on the notion that cyclist fatalities rose after the helmet law was rescinded. This was a very short period.

The editorial was followed by a letter from Jack Grossman, past Chief, Division of Plastic Surgery, Mercy Hospital. The letter is titled “Wearing a helmet vs. a lifetime of disability”.

Dr. Grossman’s letter is reproduced below. Read it and see how many things, including tradeoffs, that you can find that he overlooked.

I have listed some things I think are relevant following the letter.

“The June 21 editorial No-helmet law ushered in fatal era is so true, sadly. Not wearing a helmet is absolutely foolhardy. Common sense and good judgment must prevail. Safety helmets save lives and can minimize serious skull and complex facial-skeletal fractures, as well as destructive soft-tissue injuries.

The use of a full-face helmet, properly padded and secured, protects the lower facial and jaw areas, providing greater safety for the rider. This type of head gear is used in professional motorsports. Anything less, such as open-face or crown-only helmets, might increase the risk of serious injuries.

Consider the nature of devastating injuries that often result -- partial or permanent neurological dysfunction; extended or lifetime disability; and permanent disfigurement, to name a few. Then there are complex and risky issues of neurosurgical, orthopedic and reconstructive surgeries; extended hospitalizations usually involving specialized intensive care in a trauma center; weeks or months of rehabilitation treatments; protracted loss of income, etc.

Imagine the financial expense involved because of these injuries. The mandatory personal-injury protection vehicular-insurance benefits may have already been exhausted by the med-evac helicopter ride to the trauma center or certainly in the first 25 hours of diagnostic and specialized critical-care management once there. The cost of such care can be staggering and eventually exceed the injured's insurance coverage and the ability to pay enormous balances out-of-pocket.

What about the uninsured or underinsured rider? When this situation occurs, it becomes our -- nonriders' -- collective responsibility to pay the rider's medical bills in the form of: 1. assessed local taxes to subsidize the unreimbursed expenses for the continued operation of our county/regional trauma centers where most of the initial treatment takes place; and 2. continuously increasing auto- and healthcare-insurance rates for everyone.

These remarks reflect some of my professional experiences after many years of practice in the field. If you have friends or family members who must ride, insist that they wear proper full-face helmets. Although the feeling of the wind through one's hair is invigorating or even ''cool,'' the feeling of asphalt across one's face is definitely not. Just ask Pittsburgh Steeler Ben Roethlisberger.”

Here are some observations.

One or two observations do not convey useful information about a change in the mean. That the fatality rate rose after the helmet law was rescinded is little grounds for drawing a conclusion unless there are enough observations to justify one and the many other factors that influence the fatality rate are controlled for.

Even if helmets reduce the fatality rate, that does not imply that all people should wear helmets. It is sensible to take a risk if there is sufficient compensating gain. For some people, the enjoyment of cycling is increased substantially. The risk of fatality is low, with or without a helmet. It is easy for the former to matter more than the latter.

The increased risk associated with not wearing a helmet, other things equal, is not relevant. The risk can be reduced by driving more carefully. Cyclists who make this choice probably save innocent lives.

Helmets may reduce the fatality rate but increase the rate of serious permanent brain damage or quadriplegia. For some, death is preferable to brain damage and quadriplegia.

Not wearing helmets could lead to lower health costs. Treating more serious survivable injuries does cost more than treating less serious survivable injuries. But that ignores the possibility that without helmets, a lot of the more serious survivable injuries may be converted to deaths, which involve low health costs. Brain damaged people and quadriplegics cost a lot.

Drawing a conclusion from a particular event, Ben Roethlisberger, is about the worst logic possible. Dr. Grossman is good at rhetoric, but rhetoric is not analysis.

Dr. Grossman notes the tradeoff between the “feeling of the wind through one's hair” versus the “feeling of asphalt across one's face”. However it does not dawn on him that one can feel an awful lot of the former at only a small risk of the latter. He fails to realize that this tradeoff is the basis for the decision, not minimizing injury or health cost. If the world was about minimizing injury or health cost, cycling, or driving cars, would not be legal except for absolute necessity.

A case can be made that those most at risk when not wearing a helmet are those who are more likely to kill innocents, either in a car or on a cycle. So, perhaps it is better that they not wear helmets and, for the most part, only kill themselves.


Anonymous said...

What about helmets worn while skiing? Not only do they keep you warm, but I suspect they save lives. All of the people that I would read about in the newspaper each ski season,who died hitting a tree, never had a helmet on. Not proof. But the parents of the last 18 year old from Texas who died not wearing a helmet probably wish their son had had one on. But sometimes we do things because the positive outweighs the negitive. I wear a $50 helmet, or rent one for $5/day, keep warm, and have a better chance of keeping my brain intact if I hit a tree, which happens more often than you think when you like to ski in the trees and you're not an expert skiier. I'll choose the helmet.

TOG said...

I did not choose to wear a helmet when skiing. I found them uncomfortable. I compensated by not pushing my skiing. My death or serious injury rate not wearing a helmet was, I'm confident, much lower than yours with a helmet, not that that proves things either way.

How about the likelihood that helmet wearers ski more aggresively than they would without a helmet? What does this do to their probability of an accident where they will be killed or seriously injured? What does it do to the probabiliy they will injure a third person?

As you can see, things are not that simple.