Home > Uncategorized > Helmets, head injuries and “risk homeostasis”

Helmets, head injuries and “risk homeostasis”

April 11th, 2011

This week’s Jockology article in the Globe and Mail takes a look at helmets and the slippery concept of “risk homeostasis” — the idea that wearing protective equipment will cause you to take more risks and cancel out any safety benefits:

The message that Mikael Colville-Andersen offered to his audience at the TEDx conference in Copenhagen last November isn’t what you’d expect from a cycling advocate who travels the world promoting urban bike use.

“There are actually scientific studies that show that your risk of brain injuries is higher when you’re wearing a helmet, and that you have a 14-per-cent greater chance of getting into an accident with a helmet on,” he said. “These are not things that we hear about too often.”

With hockey head shots in the news, and revelations that ex-players like Bob Probert suffered from a form of brain damage called chronic traumatic encephalopathy, head protection is a hot topic. But Mr. Colville-Andersen’s controversial anti-helmet crusade offers a reminder that technology and equipment, on their own, can’t keep us safe. We have to consider the underlying factors that influence our risk-taking decisions – and those of the people around us… [READ THE WHOLE ARTICLE]

UPDATE April 11: Lots of e-mails and comments on the Globe site: this is clearly a controversial topic, so I’d like to expand on a couple of points. The truth is that I started working on this article with the idea of presenting the counterintuitive research that Mikael Colville-Andersen discusses in his TEDx talk, showing why helmets are actually a bad idea. But when I dug into the literature, I found that the picture was much more complicated than the way he portrayed it.

There are really two separate questions: physics and public policy. The first is fairly straightforward and asks whether, in the context of certain types of mishaps that sometimes occur on bicycles, a helmet will significantly reduce the severity of your injury. In the lab, we can clearly see that helmets can mitigate the effects of certain impacts. It’s much harder to show that this is the case in the real world, because we can’t have access to “controlled” scenarios of people going head-over-heels with and without helmets. And statistical studies of injury rates are hindered by all sorts of very serious limitations (e.g. we don’t actually know how cycling rates change, let alone traffic conditions, road surfaces, cycling skills, etc.)

Now, one could argue (as many people do) that the lack of crystal-clear epidemiological evidence of reduced cycling-related head injuries is PROOF that helmets don’t work. This is specious. Just because something is difficult to prove doesn’t mean that it’s not true. We can debate where the burden of proof should lie, but my personal assessment of the laboratory data, in combination with the admittedly circumstantial epidemiological data, is that there are certain situations in which I’d be very glad to have a helmet on my head. I certainly accept that other people might look at the same data I looked at and decide that helmets aren’t worthwhile – after all, risk calculation is a personal thing. But those who claim that it’s “proven” that helmets make no difference whatsoever in the context of individual accident scenarios are simply delusional, in my opinion.

Where Colville-Andersen is more convincing is in his public policy arguments, rooted in some of the factors I discuss in the article (risk homeostasis, safety in numbers, etc.). There have been dozens and dozens of studies on cycling injury rates and how they changed (or not) with the introduction of helmet campaigns and laws. My impression after reading through many of these studies: there are more studies supporting the efficacy of helmets than there are null studies, but the results are surprisingly weak and the overall conclusions are equivocal at best. All of the studies are plagued by serious methodological challenges inherent in trying to study this question. There are certainly plenty of studies that forcefully conclude that helmets are either good or no good, and plenty of people who cherry-pick those results in order to claim that the debate is settled one way or the other. But if you open both eyes and look at the totality of the data, I don’t believe there’s enough evidence to reach a conclusion either way.

And that leaves us with some interesting policy debates. If the overall effect of helmets is weak at best, are we justified in imposing a helmet law on children? How many cases of brain damage in Ontario would have to be avoided each year to make such a law worthwhile? One? Ten? 100? 0.1? These aren’t science questions, they’re policy questions. They’re worth debating – certainly, I’m more open to the idea of scrapping helmet laws than I would have been before watching Colville-Andersen’s talk. But as I concluded in the Globe article: based on what I learned from going through all this literature, I’ll still be wearing a helmet when I bike.

  1. Phil Koop
    April 11th, 2011 at 15:25 | #1

    I am not going to say anything about helmet use, as it is a subject that tends to make people foam at the mouth. However, bicycle helmets are only a footnote in the theory of risk homeostasis (though of course, mentioning risk homeostasis in any particular activity tends to anger people who are interested in that activity.) Anyway, I was surprised that your Globe and Mail article didn’t mention the Canadian angle: the name most associated with risk homeostasis is this guy Gerald Wilde: http://psyc.queensu.ca/target/.

  2. Lurker
    April 11th, 2011 at 15:25 | #2

    I’ve often said the best way to reduce injuries in American Football would be to play without safety equipment.

    Someone should compare its injury rates and types to those of Rugby. The rugby player doesn’t have the same disregard for his safety when tackling (or trying to break a tackle) that a gladiator in plastic armour does.

  3. Brad Kilburn
    April 11th, 2011 at 16:26 | #3

    While Alex does address Colville-Andersen’s point of risk compensation, he ignores 2 other points that would directly affect the views of his opinion on whether or not cyclists should wear helmets.

    First point missed, cycling is not dangerous.

    Try as they might helmet proponents cannot claim cyclists receive head injuries to any greater degree than others.

    Second point missed, cycle helmets are not intended for and cannot provide any protection against impacts with motor vehicles.

    Cycle helmets are tested by a simple drop from 2 meters to it’s crown. In no way is that a representation of what happens when cyclists are impacted by motor vehicles.

    Also missed in the article is the fact that the children in Ontario who were subject to a helmet law, were also subject to a lack of enforcement of the law and consequently a level of helmet usage that was consistent with usage levels equal to pre-law levels. A drop in fatalities with no increase in helmet usage cannot be credited to helmet use.

    Alex has fallen for the oldest tricks in the “Helmeteer” book, he assumes cycling is dangerous and that a helmet is a match for cycling’s greatest danger. Both are not true and have been effective at reducing the number of people who cycle

  4. alex
    April 12th, 2011 at 00:19 | #4

    Thanks for the comments, folks. Phil, you’re right on both counts: I should have mentioned Gerald Wilde, and this topic is one that gets people excited! There are already 140+ comments on the Globe site, and I’ve received far more e-mails than normal about the article. The good news is that comments seem to be equally split between “How can you not see that helmets save lives, you idiot? You’re setting a bad example for kids!” and “How can you not see that helmets do nothing and reduce cycling rates, you idiot?” That suggests that I probably struck the right balance…

  5. alex
    April 12th, 2011 at 00:39 | #5

    I’ve added a few thoughts as an update to original post above that may help clarify my thinking a bit. But just a quick note: Brad, what you call “falling for the oldest tricks in the ‘Helmeteer’ book,” I call “reading the actual studies and drawing my own conclusions.”

    For instance, you say there was no increase in helmet usage associated with Ontario’s helmet law. Parkin et al. found that helmet use among children in Ontario went from 4% in 1990 to 16% in 1991, 25% in 1992, stabilized at 45% in 1993-1995, then increased to 67% in 1996 and 1997 after legislation was introduced. After that, it declined in poor neighbourhoods and increased in rich neighbourhoods. Cycling rates among children didn’t decline after the law; head injuries did, twice as much as in provinces that didn’t introduce helmet laws.

    Is this irrefutable proof? No. Are there other studies of helmet law introductions that reach different conclusions? Yes. But don’t assume that anyone who disagrees with you must have been hoodwinked by a bunch of helmet fanatics.

  6. Brad Kilburn
    April 12th, 2011 at 02:15 | #6

    It’s my understanding that the study about Ontario youth compared two time periods that both had the same levels of helmet use and what I’m interested in is being clear and drawing conclusions from clear information.

    I’d be interested to see just which studies show bicycle helmets are effective in collisions with motor vehicles (because even helmet manufacturers are clear that they are not made for such collisions), and what information shows people on bikes injure their heads more often than people who are not on bicycles.

  7. alex
    April 12th, 2011 at 03:02 | #7

    “It’s my understanding that the study about Ontario youth compared two time periods that both had the same levels of helmet use…”

    Where does this understanding come from? Did you read the papers? Here’s a link to one of the Ontario studies: the conclusion is “This study showed that bicycle helmet use by children increased significantly after helmet legislation.” And here’s the study on non-fatal head injuries, which decreased by 45% in the four helmet legislation provinces but only by 27% in the other provinces. The paper emphasizes that helmet use did increase after legislation in all cases where it was measured.

    “I’d be interested to see just which studies show bicycle helmets are effective in collisions with motor vehicles…”

    Oh, come on. Is this a serious argument? Nobody is claiming that helmets are going to help you if you’re run over by an SUV. On the other hand, if you swerve to dodge an erratic SUV on a crowded street and hit the curb, you could easily end up going head-over-heels at a low or moderate speed without even touching the motor vehicle. Is that risk high enough to merit wearing a helmet? Well, that’s up to you.

    “what information shows people on bikes injure their heads more often than people who are not on bicycles”

    What, precisely, is the study that you think would answer this question? Or to put it another way, are you asking about a purported lack of scientific evidence, or posing a rhetorical question?

  8. Brad Kilburn
    April 12th, 2011 at 03:41 | #8

    If a proposition is made to alter behavior (in this case for cyclists to wear helmets) there should be some reasoning and evidence to show that the proposition is a good one.

    Now there is no doubt cyclists do suffer head injuries, but so do others. Why should cyclists wear helmets and not pedestrians? The tests cycle helmets go through mean they offer the same protection for pedestrians and pedestrians suffer the same degree of head injuries as do cyclists.

    And it is on your inference that cyclists wear helmets because they ride on the road with motor vehicles yet helmets are made only for simple falls that do not involve third parties and do not involve, in any way, shape or form, any involvement with motor vehicles.

    Make no mistake, I am not saying helmets are not without their worth, or that someone may not benefit from wearing one, but the benefit of wearing a helmet is almost surely less than most people think and the focus on their use has not improved safety for people riding bicycles. In fact it is a valid argument that this focus has worsened safety for cyclists by distracting people from other far more effective methods of improving the safety of people on bikes.

  9. alex
    April 12th, 2011 at 04:30 | #9

    Brad, I agree with your last paragraph. That’s why I wrote the article, to bring these arguments to a wider audience.

    As for the rest of your comment, I think we’ve reached a point where no further progress will be made. You’re still searching for “some reasoning and evidence” to suggest that helmets might offer a benefit. Glance up the screen and you’ll see the links I provided to studies showing that head injuries in Ontario decreased after the helmet law. You dismissed that evidence (apparently without having read it) because you claimed helmet use hadn’t changed after the legislation, even though the studies show that it jumped from 45% to 67%. It’s pretty clear that no evidence I offer is going to change your mind.

  10. Brad Kilburn
    April 12th, 2011 at 06:55 | #10

    Alex, please notice that my primary concerns are twofold. 1, the probability of injury and 2, effective protection in the most dangerous of all collisions, those with motor vehicles, something you spelled out quite clearly.

    I haven’t dismissed the evidence that helmets can reduce the severity of certain types of injuries cyclists can receive, but I do doubt there is evidence that helmet use has reduced the fatality or severity of serious injuries that result from collisions with motor vehicles. In fact even if a helmet could prevent such injuries, most cyclist fatalities would still occur because even when a cyclist death is listed as a result of head injuries, in the majority of cases there are other injuries that result in death regardless.

    I am quite open to believe there can be evidence to the contrary but claiming helmet can reduce the severity of an injury from a simple fall can be applied to the much different condition of an impact with a motor vehicle is a dangerous assumption and not one that should go unchallenged as the notion that cyclists hold a particular risk should be

  11. alex
    April 12th, 2011 at 07:56 | #11

    Okay, perfect, we agree. As I said earlier, “Nobody is claiming that helmets are going to help you if you’re run over by an SUV.”

  12. Brad Kilburn
    April 12th, 2011 at 12:29 | #12

    I think we agree on a number of points, but your Globe article spelled out that the prime reason for wearing a helmet while on the road is an impact with an SUV, no matter how unlikely, while ignoring the same relative risk of this happening while on foot.

    [The article says nothing of the sort, so please stop repeating this lie. -AH]

  13. Brad Kilburn
    April 12th, 2011 at 12:44 | #13

    Further to my points here is a report from the CIHI on major head injury in Ontario

    http://secure.cihi.ca/cihiweb/en/downloads/bl_otr_mar2004_1_e.pdf

    and a report written by the director of one of Europe’s leading test labs for helmets of all kinds

    http://secure.cihi.ca/cihiweb/en/downloads/bl_otr_mar2004_1_e.pdf

    an article on a report that shows helmets do reduce injury, but do not protect in collisions with motor vehicles

    http://www.imperial.ac.uk/college.asp?P=2250

    and some more recent research that says,

    “there is “no net protective effect” from wearing a helmet, because they actually increase the risk of neck injuries.”

    http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10718438

  14. Brad Kilburn
    April 12th, 2011 at 15:01 | #14

    Also, California saw a case in which the judge commented that the standards helmets are tested to are not true performance standards, only measure certain areas on a helmet that are not involved in the majority of head injury accidents, and are not sufficient enough for making a product safe enough for use on the streets

    http://www.stc-law.com/prodliability.html

  15. RH
    April 12th, 2011 at 15:20 | #15

    Here’s what appears to be a quite comprehensive overview of research on the subject.

    http://www.cyclecraft.co.uk/digest/helmet_research.html

  16. Brad Kilburn
    April 12th, 2011 at 15:48 | #16

    and here is a site recommended by both the ECF and the UK government for information on bicycle helmets

    http://cyclehelmets.org/

  17. Phil Koop
    April 12th, 2011 at 17:33 | #17

    I find that I still have the strength to resist offering an opinion on bicycle helmets per se.

    However, I am going to bend my rule a little bit on the subject of non-cycling helmet use, which is something to which Brad alluded. Even granting that helmets are effective at preventing cycling injuries, it is a very long jump indeed to conclude that expensive advocacy or legal mandates of helmet use is justified. It is seems certain that, in Canada, more injuries could be prevented by wearing helmets in cars than on bicycles; yet this is never advocated. The reason is that helmet advocates are not seeking to address a public health issue; if they were, they would reason in the other direction, from problem to solution. (Anecdote: my wife, who sees many patients with acquired brain injuries, would say that one activity for which helmets ought to be required is downstairs trips to the urinals in bars; apparently, a source of many sub-durals.)

    Anyway, it is impossible to write an even-handed article on cycling helmet use because the issue is so politicized; the subject is a species of assuming the conclusion.

  18. Phil Koop
    April 12th, 2011 at 17:36 | #18

    Anecdote #2: much research on helmet use is not quite, shall we say, top-drawer. (In part because its hard: ethically, such research must be observational and there are always confounding factors.) There was a guy associated with one of the Toronto hospitals (sorry, I can’t bring his name to mind) who wrote a survey paper analyzing much of this research, concluding, more or less, that the research is inconclusive. My wife has seen him cycling down University Avenue … wearing a helmet.

  19. Brad Kilburn
    April 12th, 2011 at 18:36 | #19

    Indeed. Research on the topic is often flawed and this is one of the prime issues in the debate.

    Transport Xtra magazine ran an article by a Transportation planner who chose to examine the topic for his masters of Science dissertation.

    http://www.transportxtra.com/magazines/local_transport_today/news/?id=14073

    In the article, Mr. Burton says,

    “I started work on an MSc dissertation about cyclists’ views of cycle helmets and the risks of cycling and, as part of that, I undertook a wide literature review. Although aware of the controversy about helmets, and sceptical of the claims made for them, I was unprepared for the overt bias in much research, with some researchers apparently reaching conclusions before starting work; policy-based evidence making, as one observer commented.”

    There is profit potential to produce a study favorable for invested interests and this is nothing new. Money talks and the profit potential of selling fear is sometimes too great to resist.

  20. alex
    April 12th, 2011 at 21:51 | #20

    RH: I wouldn’t call that a “quite comprehensive overview”: it ends in 2002, and was curated by one of the leading anti-helmet crusaders.

    Phil: “Anyway, it is impossible to write an even-handed article on cycling helmet use because the issue is so politicized; the subject is a species of assuming the conclusion.”

    I disagree. The writing of the article and the response to the article are two separate entities. I approached the article with no dog in the fight. I looked at the research, and summed up my understanding of it as best I could, with nothing to gain or lose from any position taken. It’s the response that has been entirely politicized, and frankly divorced from any serious pretense of disinterested scientific inquiry.

    “There was a guy associated with one of the Toronto hospitals… who wrote a survey paper analyzing much of this research, concluding, more or less, that the research is inconclusive. My wife has seen him cycling down University Avenue … wearing a helmet.”

    That’s pretty much exactly the conclusion I reached. I read the papers that purport to show helmet benefits; I read the papers that purport to show no benefits (despite the irritating assumption from helmet opponents that I just waltzed up and drew my conclusions without actually reading the research). I don’t believe it’s possible to draw a conclusion at this point, any more than it’s possible to guarantee one way or the other that there’s life elsewhere in the galaxy. There are simply too many uncertainties in the data sets we have available to us.

    So taking what we know, and weighing the relative potential harms on either side, I choose to wear a bicycle helmet. Others may choose not to, and by all means the merits of public policy initiatives should be debated. But that debate shouldn’t start with the specious claim that the question of whether bicycle helmets can mitigate harm in certain accident situations has been settled one way or the other.

  21. Brad Kilburn
    April 12th, 2011 at 22:06 | #21

    But isn’t the choice to wear a helmet predicated on a concern, or fear of being on the receiving end of a nasty bump to the head?

    Certainly we know people fall and do this everyday yet the concern we have that leads us to consider wearing a helmet is a disproportionate one when on a bike than off the bike.

    I maintain that this concern is cultural, rather than factual, and is a result of how cyclists are viewed within North American ( and Australian/ New Zealand) culture.

    Wearing a helmet on a bike is a reflection of cycling’s status, not a reflection of it’s actual safety record

  22. Phil Koop
    April 12th, 2011 at 22:38 | #22

    I already know that you disagree; what I don’t know, because you have not told me, is what are your grounds for disagreement?

    To recap, my assertion is this: by writing an article about bicycle helmets, you are taking for granted that there is something special about cycling compared to other human activities that might require helmet use. That is “begging the question” in the traditional sense; as I remarked, this is a species of assuming the conclusion.

    If you are just even-handedly considering the issue based on the evidence, why did you not start by looking to see which activities accrue many head injuries and might benefit from helmets? How do you know that helmets might not be more important for driving to the corner store, yachting, walking home from the pub, or whatever? Have you got any data? Any evidence? What is it?

  23. Brad Kilburn
    April 12th, 2011 at 22:42 | #23

    But isn’t the choice to wear a helmet predicated on a concern, or fear of being on the receiving end of a nasty bump to the head?

    Certainly we know people fall and hit their heads everyday yet the concern we have is a disproportionate one when we consider head injury on a bike.

    I maintain that this concern is cultural, rather than factual, and is a result of how cyclists are viewed within North American ( and Australian/ New Zealand) culture.

    Wearing a helmet on a bike is a reflection of cycling’s status, not a reflection of it’s actual safety record

  24. Brad Kilburn
    April 12th, 2011 at 22:47 | #24

    My grounds for concern regarding head injury have been submitted via a link to a report on serious head injuries in Ontario. s@Phil Koop

  25. Phil Koop
    April 12th, 2011 at 22:52 | #25

    Here is another anecdote to illustrate what I am talking about. Whenever I tackle one of the big Alpine climbs on a hot day, I always pull off my helmet. This sometimes draws looks of shock from Americans (though not from Europeans: a hint that there is more to this than safety.)

    Yet an elite runner like you can run faster on the flat than I can climb an Alp. Do you think you should strap on a helmet before that next 10K? Particularly if it’s x-country? If not, why not? Don’t tell me runners never trip and fall – I’ve seen it many times, and even done it myself.

  26. alex
    April 12th, 2011 at 23:50 | #26

    Phil, it’s only begging question in the same sense that every article I write (and I write several hundred a year) starts with an assumption that the topic I’m writing about is worthy of interest. If I write an article about whether running is or is not good for my heart, it says nothing about whether I think that bouncing on a pogo stick is good for my heart. It may be that pogo-sticking is even BETTER for my heart than running, but that’s not what my article is about. And in a world of finite time and knowledge, I can’t preface every article by saying “Clinical research has definitely proven that it’s more worthwhile for me to write about the cardiac benefits of running than of pogo-sticking and the 5,000 other possible activities that could conceivably give rise to similar benefits.” Lots of people run; few people pogo-stick, so I write about the former, while MAKING NO JUDGMENT OF THEIR RESPECTIVE INTRINSIC MERITS.

    So if by begging the question, you mean I start by assuming the question of whether bike helmets is of interest, then yes, that’s true. But if you’re implying that the decision to write an article implies any a priori assumption about WHETHER bike helmets are effective, or whether they’re more justified than protective gear in other comparable activities like walking, then I vehemently disagree. The former was the question I set out to answer, and the latter is a question beyond the scope of my inquiry.

    As for your anecdote about the Alpine climbs, I’m sincerely puzzled on multiple levels. In my car, I sometimes drive very slowly along a driveway to a garage. If I told you that, under those circumstances, I stop and unscrew the bumpers from the front and back of my car, would that convince you that (a) car bumpers are a waste of time and money, and (b) shopping carts should be fitted with enormous car bumpers, since they sometimes move as fast as I do when I’m parking?

    More to the point — and this is what I’m finding very frustrating — I’ve never argued that there’s compelling evidence in favour of helmet use. As I said in my previous comment, “I don’t believe it’s possible to draw a conclusion at this point.” I’d understand all these comments if I’d claimed that the research definitely showed that helmets are effective on a population level. Why is it that those opposed to helmet use seem unable to distinguish between agnosticism, atheism, and fundamentalism, as it were?

  27. PB
    April 12th, 2011 at 23:54 | #27

    Alex, I think the Globe article was just too short or something. Without you and Brad going at, I would be lost.
    Mikael Colville-Andersen’s talk sited lots of studies and country-wide attitudes in bike helmets. A few studies from children in Ontario is a drop in the bucket. Anyway he said less people ride bikes when helmet laws are introduced — the study from Ontario showed this. Plus, the riding habits of children and adults can’t be compared.

    And, how in the hell do you enforce a helmet law. Will I get chased down and arrested in Vancouver. Canada goes nuts on this kind of stuff for politically bias reasons.

  28. alex
    April 13th, 2011 at 01:00 | #28

    “Mikael Colville-Andersen’s talk sited lots of studies and country-wide attitudes in bike helmets.”

    I’d argue that he said a lot of things, but he didn’t cite a lot of studies. There’s a big difference.

    “A few studies from children in Ontario is a drop in the bucket.”

    Well, okay, here’s a Cochrane Review of five studies, from 2009, that concludes “Bicycle helmet legislation appears to be effective in increasing helmet use and decreasing head injury rates”: http://www.ncbi.nlm.nih.gov/pubmed/18646128

    Again, I’m not arguing that the science is settled. I’m just arguing against this habit of holding the two sides of the debate to different standards of evidence.

  29. Frank Krygowski
    April 13th, 2011 at 02:13 | #29

    @Phil Koop

    I second Phil’s point. You, like many others, address whether bike helmets make cycling safer. It implies that cycling _needs_ to be made safer, presumably because it is a significant risk of serious head injuries.

    Yet the data I’m aware of says the opposite. For example, John Pucher’s paper “Making Walking & Cycling Safer…” somewhat inadvertently shows that U.S. cyclists are three times as safe, per km, as pedestrians. Head injury (or rather, brain injury – we should stop conflating the two) is no more prevalent a cause of cycling fatalities than pedestrian fatalities. For those concerned with societal costs (rather than risks to individuals), cyclists suffer fewer than 1% of the brain injury fatalities in the U.S., and the same is probably true of Canada, whereas motorists suffer nearly half, despite seat belts and air bags. In many years, Canadians suffer more fatalities by falling out of bed than by riding bikes.

    Why, then, even bother examining effectiveness of bike helmets? By any rational standard, they are no more needed than, say, walking helmets, motoring helmets, stair descending helmets, ladder helmets – you get the picture.

    In fact, I’m sure that bike helmets currently on the market would be more effective for those bigger sources of brain injury than they are for cycling!

  30. alex
    April 13th, 2011 at 07:50 | #30

    “Why, then, even bother examining effectiveness of bike helmets?”

    As a reader pointed out via e-mail, I’m definitely going to need a helmet to protect myself from all this banging of my head against the wall.

    Frank, the reason it’s worth examining the effectiveness of bike helmets is because many millions of people wear them. You and others suggest that the reasons we wear them are flawed — well, then all the more reason that I should examine the evidence to explore whether they actually help, no? I mean, in that sense, I’M ON YOUR SIDE. The fact that I chose to write this article suggests that I don’t accept the widespread orthodoxy that helmets “must” help us.

    Do you understand that? Do you understand why, as a journalist, I’d choose to investigate a safety device that millions of people wear rather than a hypothetical device that no one wears?

    “You, like many others, address whether bike helmets make cycling safer. It implies that cycling _needs_ to be made safer, presumably because it is a significant risk of serious head injuries.”

    That’s simply not true. My decision to address whether bike helmets make cycling safer “implies” that I was wondering whether we should continue to advocate the use of bike helmets.

    To put it another way, if I’d come to you a few weeks ago and said, “I’m thinking of writing an article that digs into the actual research on bike helmets and injury rates, because I’d like to find out if all the bike helmets laws and advocacy are actually based on solid evidence, or whether they’re misguided crusades that waste time and money,” I’ll bet you and Brad and Phil would have said “Great idea!” The reason you’re critical now isn’t that I wrote the article in the first place; it’s that the conclusions I drew didn’t match your own.

  31. Brad Kilburn
    April 13th, 2011 at 15:09 | #31

    Morning, Alex. I’ve come back to the discussion to see where the it had run and noted your frustration. I feel your pain, I have a similar issue, but I think that’s OK because it’s through our differences that we can gain a better understanding.

    Fair enough, I can see your article doesn’t come to any conclusions on whether or not helmets are effective and doesn’t address the issue of relative safety. It’s about risk compensation and if that’s a reasonable enough factor to consider when using a cycle helmet. (Is this right?)

    I know I’m appreciative that such an article finds its way into “Canada’s National Newspaper”. As in the quote by Mr. C-A in his Ted X talk that started the whole thing off, I find this is a thing we don’t hear about too often.

    I think my chief frustration lies in the fact that – after your research on whether helmets are effective or not and if risk compensation affects behavior of those who wear helmets while riding bicycles results inconclusively – you write:

    “The key difference between cyclists and rubgy or hockey players, of course, is the presence of a powerful external agent: cars. The wise cyclist may join Mr. Colville-Andersen’s crusade to make urban cycling so widely accepted that helmets seem unnecessary – but he or she will still wear one just in case.”

    To me, this shows risk compensation exists. That cyclists will compensate for the risk of riding a bicycle by wearing helmets.

    I think this is a better compensation than another form of risk compensation that a number of other people take part in- by stopping to ride bicycles altogether. This is something that Mr. C-A points out has pointed out that has happened when helmet promoters conduct campaigns that emphasize the dangers of cycling, and that’s just bad for everyone because everyone benefits when someone chooses to cycle.

    I also think that by writing that, that powerful external agent, the car, is the reason for using a helmet, “just in case” is a conclusion that cycle helmets provide adequate protection in conflicts with these external agents in spite of your claims that there is no solid case for their worth.

    Don’t make the mistake that by mentioning that helmets have limitations, and protection beyond these limitations is not available, that I’m opposed to helmet use, I’m not. I’m in favor of helmet use when it is warranted, and in conditions when a helmet can provide protection. I think your statement implies helmet use on the streets is warranted and can be effective and I believe otherwise.

    This all brings us back, full circle to M C-A’s Ted X talk. His talk only flirts with the risk compensation argument. He doesn’t even call it out by name and mentions it only in passing. His talk was more about how our culture of fear can make things less safe by scaring the public out of the very things that can benefit it. Bicycle helmet promotion and laws have done this in a measurable way and I think the more people know about this issue, the better off we’ll all be.

  32. Frank Krygowski
    April 13th, 2011 at 17:22 | #32

    You wrote: “Frank, the reason it’s worth examining the effectiveness of bike helmets is because many millions of people wear them. You and others suggest that the reasons we wear them are flawed — well, then all the more reason that I should examine the evidence to explore whether they actually help, no? I mean, in that sense, I’M ON YOUR SIDE.”

    I’m fine with unbiased examinations of the efficacy of helmets, given that their efficacy seems greatly exaggerated. I just believe you’re missing a more fundamental question: Is there really a _need_ for a helmet during ordinary bike riding? (I’m excluding activities like racing mountain bikes down rocky mountain trails.)

    I believe it’s important to question that supposed need. That’s largely because I’ve found much evidence that it’s imaginary. And the false belief in that need has both real and potential downsides.

    For one thing, helmet marketing and promotion has convinced much of the public that any ride on a bike is life threatening. This has, I believe, reduced cycling levels, and directly caused a net loss in public health as well as other social and environmental harm.

    For another thing, if we don’t question the purported need for helmets, but do convince society that current helmets are ineffective, a likely result would new standards for thicker, heavier, less convenient helmets, which would further dissuade cycling. Those would themselves receive unquestioned promotion from some and skepticism from others. The cycle (so to speak) would continue.

    So again, I’d recommend you examine the more fundamental question: Is cycling unusually dangerous, especially regarding serious brain injury? Note, this wouldn’t require you to retract anything you’ve already written. In fact, you could consider it a useful topic for a follow-up article.

    As it is, you’re in a similar position to that of a journalist researching whether it’s better to buy our bottled water in blue bottles or in green bottles; when the real question is, “Why on earth are we wasting money on bottled water?”

    See if you like this:
    http://www.bicyclinglife.com/SafetySkills/SafetyQuiz.htm

  33. Phil Koop
    April 13th, 2011 at 17:30 | #33

    “If I write an article about whether running is or is not good for my heart, it says nothing about whether I think that bouncing on a pogo stick is good for my heart.”

    Of course it does! I can infer reasonably (though not with certainty) that you don’t think pogo is a significant mode of exercise – even if would be effective. Your claim here can only be credible to someone who rejects the logic of probable inference; but you won’t get very far in life if you insist on deductive logic as the only valid mode of reasoning.

    Look, I understand that you are proud of your work, but there are zillions of helmet stories nearly identical to yours, a new batch every year. I readily accept your claim that you have done more research on the subject than the typical journalist and understand the issues better; yet the result is the same. As is the commercial result: it is a reliable way to attract interest because of the passions it inflames. That is why it a perennial favourite; a file story, really.

  34. alex
    April 13th, 2011 at 23:38 | #34

    @Frank: You write “I’m fine with unbiased examinations of the efficacy of helmets, given that their efficacy seems greatly exaggerated. I just believe you’re missing a more fundamental question.”

    Okay, fair enough. I wrote Article A, you believe I should have written Article B instead. That’s fine: it’s, of course, true that every article that is written involves a choice about what is worthy of coverage, and those choices are perfectly open to debate. For example, I believe there should be fewer articles about Charlie Sheen in the media.

    But that’s not what Phil said and you seconded. Here’s what Phil wrote: “by writing an article about bicycle helmets, you are taking for granted that there is something special about cycling compared to other human activities that might require helmet use. That is “begging the question” in the traditional sense; as I remarked, this is a species of assuming the conclusion.”

    In other words, he’s saying that by writing Article A, I assume the conclusion of Article B. But that’s simply false, and impugns both my motives and my intelligence. To re-re-reiterate, I chose to explore whether bike helmet use is evidence-based because people wear bike helmets. Whether walking is just as risky as cycling is a related but separate question, and no assumption about its answer is necessary to be curious about the question I chose to explore.

  35. alex
    April 13th, 2011 at 23:55 | #35

    @Phil: “I can infer reasonably (though not with certainty) that you don’t think pogo is a significant mode of exercise – even if would be effective.”

    As it happens, I believe pogo-sticking (and an infinite list of other sustained, rhythmic activities like cycling, kayaking, swimming) can provide more or less identical benefits to the heart, under the right circumstances. So when I write an article about the heart benefits of running, it in fact says nothing about whether or not I believe pogo-sticking can benefit the heart, notwithstanding your spurious inference.

    The reason I write more articles about running than about pogo-sticking is because more people run than pogo-stick. You may complain that in a rational world, no preference would be granted to running over pogo-sticking because their intrinsic merits are comparable. Fine.

    And you and Frank could argue that the more interesting article to write would be about whether there’s really any difference between running and pogo-sticking, and whether entrenched commercial interests and underlying cultural biases have unfairly marginalized the pogo-stick. And you’d be within your rights to do so: as I said in the comment above, every article does represent a choice about what is most worthy of pursuing.

    But the moment you imply that me writing about running begs the question and assumes the conclusion about whether pogo-sticking is as good as running for heart health, you’re no longer being fair or rational.

    “I readily accept your claim that you have done more research on the subject than the typical journalist and understand the issues better; yet the result is the same.”

    So let me sum up: my motives for embarking on the inquiry are irrelevant. The rigour with which I pursue the inquiry is irrelevant. All that matters is whether I reach the conclusion that you’ve picked before the inquiry even started. You’ll pardon me if I don’t find that a particularly fruitful model either for scientists or for journalists.

  36. Frank Krygowski
    April 14th, 2011 at 02:53 | #36

    @Frank: You write “I’m fine with unbiased examinations of the efficacy of helmets, given that their efficacy seems greatly exaggerated. I just believe you’re missing a more fundamental question.”

    Okay, fair enough. I wrote Article A, you believe I should have written Article B instead. That’s fine: it’s, of course, true that every article that is written involves a choice about what is worthy of coverage, and those choices are perfectly open to debate. For example, I believe there should be fewer articles about Charlie Sheen in the media.

    But that’s not what Phil said and you seconded. Here’s what Phil wrote: “by writing an article about bicycle helmets, you are taking for granted that there is something special about cycling compared to other human activities that might require helmet use. That is “begging the question” in the traditional sense; as I remarked, this is a species of assuming the conclusion.”

    ===================================================

    And yes, Phil is correct. If you didn’t think serious head injuries were a significant issue in cycling, you wouldn’t have been interested in the question you addressed.

    He and I have both tried to get you to take a step back and examine a larger question, one which I think would make your chosen question moot. Obviously, you’re not going to examine the larger question. It’s your blog, it’s your choice.

    Can we look forward to an article on whether kevlar running shorts reduce the number of fatal wasp stings in joggers? ;-)

  37. Brad Kilburn
    April 14th, 2011 at 03:30 | #37

    I’m still waiting for my critique. Did I get it wrong? What did I miss?

  38. RH
    April 14th, 2011 at 08:13 | #38

    I’m amazed that bicycle helmets spark such a fierce debate. Perhaps debating helmets would be a good idea.

    As to the issue whether the real issue is another issue, my thought are the following.

    Firstly, in a country where at least one province has helmet laws, and thus -rightly or wrongly- deemed it necessary to reduce injuries from bicycle accidents, the government already decided for you that bicycle safety is an issue. It is perfectly legitimate to question whether the law achieves its aim.

    Secondly, policy debates often revolve not only around constructive proof, but also around ‘defeaters’. Which question is more basic is a matter of perspective. What I mean is this.

    Suppose you are campaigning for the introduction of helmet laws. Indeed, then you wile have to convince your audience first that there is an ‘issue’ to be addressed and then that mandatory helmet use is the solution. From that perspective, the question whether there is an ‘issue’ to be addressed, is the basic question.

    However, as a campaigner for helmet laws, you do not necessarily have to show that bicycles are more dangerous than other modes of transport. I would be perfectly legitimate to say “here’s a cheap and effective way to save a few lives”. With helmets as with Kevlar pants, if it saves one life, there a case for it. Your case may also be that the traffic is generally unsafe and that bicycle safety would be a good starting point to make traffic safer.

    If you are opposed to helmet laws however, your case revolves around defeating arguments. Of course you may go about attacking the argument that cycling is unsafe, that traffic is unsafe, that the cost of saving just a few cyclists lives is too high, helmets are uncomfortable etc, but the argument that defeats all cases that can be made for helmet laws is, that helmet laws don’t save lives. From that perspective the question “Do helmets really help reduce my risk of a head injury?” is more basic.

    Of course, I am not saying that anyone who addresses a certain question is in a certain camp, but that both questions can be legitimately called basic.

  39. alex
    April 14th, 2011 at 09:45 | #39

    RH — Thanks for the thoughtful comment. I agree 100% with everything you wrote.

  40. Phil Koop
    April 14th, 2011 at 12:24 | #40

    “The reason I write more articles about running than about pogo-sticking is because more people run than pogo-stick.”

    But that’s exactly what I said! I did NOT say that I infer you think pogo wouldn’t be effective, I said that I can infer that you don’t think pogo is significant as exercise. And now you have confirmed that my inference was correct. Before you confirmed it, I could not be certain, but it was no accident that I was right: I drew a logical inference based on information.

    Back to the subject at hand. The reason that you wrote an article about helmets and cycling is that as a political issue, it is disproportionately salient compared to helmet use in other activities – or so I infer, logically, from information. But whereas the fact that people run is an excellent reason to write an article about running, the fact that people obsess about cycling helmets even as they put their heads at risk in all sorts of other silly ways is not an excellent reason to write an article about cycling helmets. On the contrary; a more noble reason to not write such an article can scarcely be envisaged.

  41. AG
    April 14th, 2011 at 15:02 | #41

    I think RH nailed it: “here’s a cheap and effective way to save a few lives”. Many decisions with regards to safety are done to some degree similarly as Pascal’s wager on religion, i.e. it costs relatively little and the reduction of risk in the worst case (or perfect case for a helmet) accident is (arguably) large. It really doesn’t matter how many studies have been done. All you need is a little empirical data “my helmet saved my life” and that’s all the justification that’s needed.

    This is an interesting subject that I have thought about in detail before because I like the seat belts, airbags, ABS, etc. in my car and I don’t own a motorcycle because I perceive it as more risky, yet I think nothing of riding my bicycle in traffic, or down a hill at 50mph or down a steep rough trail at 30mph!

    Speaking of motorcycles, one article I’ve read in the past dealt with motorcycle helmets and whether or not the current hard shells are the best for a population. Current SNELL specifications require the helmet to survive multiple blunt impacts (like hitting a curb multiple times) but the study showed that there are only a few lives saved by the hard shell in a multiple impact case, and many injuries caused by the hard shell that could be prevented by a softer shell (that you could assume would not survive multiple blunt impacts.)

    I wear a helmet even when doing an easy ride on the road, not because it’s mandatory or I feel safe, but because it’s automatic. It’s the same with using the seatbelt in a car at low speeds in a parking lot, or the blinkers when nobody is around me.

    To the commenter that made a remark about American Football…I wholeheartedly agree. Make them go to soft shell helmets with no face mask. You’ll have missing teeth, broken noses, but many less concussions and spinal chord injuries. Wasn’t the article’s original intent (at least the title) to discuss whether people take more risks when they perceive they are safer?

  42. Brad Kilburn
    April 14th, 2011 at 15:35 | #42

    I see the issue about helmet promotion, use, and laws as one of being of an ineffective solution to a non-existent problem and worsens what small “problem” there is.

    Although I can understand why some people think risk compensation isn’t a legitimate issue, it is a recognized behavior that has been observed in many situations and is something that someone who is taking part in it will not be aware that they are doing so.

    If a doctor prescribes a treatment for poor health as one of walking, in place of driving or taking the stairs instead of an elevator, it would be because it’s recognized that the benefits far outweigh the small risks and the patient’s health will improve. The same holds true for bicycle use but the public doesn’t see it that way. Or should I say, the public – in certain places in the world – doesn’t see it that way.

    Helmet use is a cultural phenomenon that has only been accepted where transport on a bicycle is seen as subservient to transport by motor vehicle. Try as the might, after decades of campaigning, helmet promoters have only convinced a small percentage of people who ride bikes all around the world that helmets are worth wearing. I think most people who ride bikes and don’t feel subservient to a motor vehicles understand that there are far better ways of being safe on a bike than wearing a helmet and that riding a bike isn’t that dangerous anyway.

  43. Brad Kilburn
    April 14th, 2011 at 17:06 | #43

    As for helmet laws, I watch with interest how the times change.

    It’s been a while since new laws for adults have been passed. Perhaps it’s because of the evidence from MHL areas that shows a politicians proclamation of, “here’s a cheap and effective way to save a few lives” has been shown to be incorrect.

    Some still do get passed of course, but they are more and more isolated are more knowledge on the issue is acquired

  44. Brad Kilburn
    April 14th, 2011 at 19:46 | #44

    and btw, I’m taking it that cyclists wearing a helmet “just in case” is evidence that cyclists engage in risk compensation.

    If there wasn’t a worry (or fear) of injury, there would be no need for the helmet.

    Remove a consequence, and behavior alters. Is it really any more complicated than that?

  45. alex
    April 14th, 2011 at 23:21 | #45

    Phil, let’s take a step back and remember what we’re now arguing about. We’re arguing about my state of mind: what I believed before writing the article, since you explicitly stated that the mere act of writing the article means I was assuming a particular conclusion.

    You now say, regarding our pogo stick example, “I said that I can infer that you don’t think pogo is significant as exercise. And now you have confirmed that my inference was correct. Before you confirmed it, I could not be certain…

    Exactly. You pointed out in a previous comment the difference between deductive logic and inference, and you acknowledge here that you can only make inferences as to what I believe. And it may be that, from within your frame of reference on this issue, your inference about my beliefs on the relative dangers of cycling and walking was reasonable.

    But when it comes to knowledge of my state of my mind, one of us is in a rather privileged position. I’ve told you that I didn’t hold any preconceived conclusions about the relative dangers of cycling and walking; and in fact, I still have no conclusion. I agree that it’s an interesting question, but I don’t have the data, therefore I don’t know the answer.

    In this situation, your inference — however reasonable it may have seemed to you at the time — clashes with direct facts. As we’ve painstakingly established with the pogo-sticking analogy, there is no deduction possible about my state of mind, only inference. So your continued insistence that your inference of my state of mind is more reliable than my direct knowledge of it means that either you think I’m a liar, or you’re allowing your strong feelings on this question — “a subject that tends to make people foam at the mouth,” as you astutely pointed out in the first comment on this thread — to cloud your thinking.

  46. Brad Kilburn
    April 15th, 2011 at 15:06 | #46

    for the record, the 14% stat comes from the Norwegian Transport Økonomisk Institut (TØI).

    and the concept of risk compensation has been around since Plato’s time

    http://blog.talkingphilosophy.com/?p=1143

  47. Frank Krygowski
    April 15th, 2011 at 15:20 | #47

    AG wrote: “I think RH nailed it: “here’s a cheap and effective way to save a few lives”. … it costs relatively little and the reduction of risk in the worst case (or perfect case for a helmet) accident is (arguably) large.”

    And yet, that logic is not applied to any of the the most common source of fatal brain injury in North America. You may love your car’s seatbelts and airbags, AG; but the vast majority of North Americans, even avid cyclists, are far more likely to die of brain injuries inside their car than while riding their bikes. Most auto deaths are due to brain injuries, just as are most pedestrian deaths and most accidental deaths in general, although this is not brought to the public’s attention.

    About two weeks ago in my area, there was yet another auto fatality. The newspaper specifically stated that the cause of death was brain injury, and specifically stated that the driver was belted in, and his airbag worked. This was a single car crash, leaving the road in a 35 mph zone.

    By your logic, it was foolish in the extreme for this person to drive without a helmet, because a helmet “arguably” might have saved him. Yet the public never thinks about the benefits of helmet use for the activity causing the greatest number of brain injury deaths.

    Why? Because despite causing about half of the nation’s brain injury deaths, motoring inspires no helmet articles. Despite causing fewer than 1% of the brain injury deaths, bicycling regularly inspires helmet articles. It’s all part of the “bicycling is dangerous” fallacy.

    AG: “It really doesn’t matter how many studies have been done. All you need is a little empirical data ‘my helmet saved my life’ and that’s all the justification that’s needed.”

    Wrong. Anecdotes are not data.

    An oversized, fragile hat will obviously convert many a near miss to a dent in styrofoam. The dent may convince the wearer his life was saved. But national data from several countries show there has been no per-cyclist reductions in fatalities (or even serious brain injuries) as a result of helmet use. Almost all “my helmet saved my life” stories are mistaken, even if they are sincere.

  48. April 15th, 2011 at 19:01 | #48

    For reference, the study Brad is refering to is here: http://samferdsel.toi.no/article27673-1153.html – it doesn’t mention 14%, but says something about the change in behavior. Run it through Google Translate if you don’t read Norwegian.

  49. alex
    April 19th, 2011 at 21:55 | #49

    @Arve Bersvendsen
    Thanks, Arve — good to have some Norwegian expertise on the site! :)

  1. April 15th, 2011 at 10:28 | #1
  2. May 3rd, 2011 at 00:18 | #2