BBC programme in the Sliced Bread series: "Cycle Helmets"

[Jdsk]

BBC programme in the Sliced Bread series: "Cycle Helmets":
https://www.bbc.co.uk/sounds/play/m001n21k

I've only listened to the second half and bits of the first half so far. There's a discussion with Walker: I'd always listen to what he has to say. And I totally agree about the importance of being very clear about the different questions. That's one of the key steps that would improve the discussion in this forum.

Jonathan

[colin54]

Thanks for the link Jonathan, quite hard to cover all the ins and outs of the subject in half an hour but they had a good go.
For what it's worth, sometimes I wear a helmet (longer journeys in the spring/autumn & winter - slippy roads). Sometimes I don't - cycling to the shops (about a mile on cycle paths) and during the summer I wear a sun hat. None of my thinking behind my choices would bear close
analytical scrutiny I don't suppose.

[Nearholmer]

I caught it accidentally, and thought it was very good.

[Pete Owens]

Nearest, to balance I've heard from the BBC. Though there still was an difference to how the two contributors were treated.

The first was an expert on helmet testing - and subjected to very little challenge. This was fine when he was describing how helmets were designed to absorb energy (there isn't really any argument on that score). There were interesting bits about the compromises involved by introducing air vents and so on. The challenge should have come when he veered into advocacy. There are a lot of dots to join between
"A helmet will offer protection if you hit your head" to
"You should wear a helmet for the small proportion of the time your happen to be riding a bicycle, but not at other times".
No attempt was made to quiz him about the question raised by the listener about helmet mearing increasing crash risk (this was after all the subject of the programme).
He was not challenged when he claimed that the research on the subject was overwhelming.
He was not asked to comment on whole population studies in states that have introduced compulsion.
He was allowed to get away with the rather outrageous claim that the biases in hospital trials made their results stronger rather than weaker,
Basically he was treated as THE EXPERT.

Walker was impressive, and allowed, to make his case. The discussion was good and actually allowed him to expand the points he was making, but every point he made was challenged. I think the case was more powerful, exactly because He was not taking an ideological position.

And when it came to the summing up, basically it was the helmet testers argument, "Cycle helmets protect you head therefore you should wear one" with Walkers points as an interesting but irrelevant aside. And it was left to the original questioner who had actually wanted to know about risk compensation to point out that his question had not been addressed at all (though I think Walker's contribution to the programme was rather more useful than would be the case had they invited John Adams)

[axel_knutt]

it was left to the original questioner who had actually wanted to know about risk compensation to point out that his question had not been addressed at all

Actually, he didn't specifically introduce risk compensation until the end, his original question was about the confusing proliferation of helmet designs, and the simple question of do they make you safer.

The presenter's attempt to redefine the listener's question about risk compensation, and his tone of voice when he was pinned down said all you need to know about the attitudes and agenda. The majority of the population think risk compensation is barking mad, and people don't want to look barking mad.

Since everyone has already made up their mind, and isn't interested in evidence, the Spiegelhalter-Goldacre quote was most apt.

Very disappointing, as is invariably the case with this subject.

[Mike Sales]

The majority of the population think risk compensation is barking mad,

The idea that people do not modify their behaviour according to the risk they perceive seems very odd to me.

[slowster]

The person they chose to make the case for helmets works at the Virginia Tech Helmet Lab, an organisation which exists to test helmets and therefore presumably has a strong vested interest. As per Pete Owens' comments above, his argument appeared to be little more than to take his word for it that the scientific evidence is overwhelmingly that people should wear helmets.

I was unimpressed by his describing the phenomenon of risk compensation as 'a philosophy', a term which implied that risk compensation is not something which can be analysed using the scientific method, but is instead something which some people choose to believe in like a religious faith. When someone who is supposedly a scientist criticises another scientific field of study using not the scientific approach, but instead the language of faith/belief, that strikes me as 'reverse projection'. In other words, he absolutely believes in helmets, but cannot make a good scientific argument against the science that suggests the opposite, so he denies that the opposing science is 'science'.

I did not think it was a particularly good programme, and I am not convinced that the premise of getting advocates for 'both sides' is a good way to present complex and often very nuanced or finely balanced issues. My rule of thumb for a good scientist speaking on such a programme is that it should be difficult to tell the pro- and anti-helmet scientists apart, precisely because the issue is nuanced and complex, with a lot of the evidence comprising conflicting - and in some cases questionable - studies. Two scientists representing the two sides of the argument who nevertheless say very similar things and are in agreement about the uncertainties of the science does not make for 'good' programming.

[Stevek76]

There was an irony in Walker's stress for defining the question in that subsequently the VT guy was allowed to state an unchallenged claim about the data on helmet law efficacy by answering a different question than had been put to him.

The point that had been put to him was that of cycling UK's position was that laws and even very likely promotion are bad because the total potential public health gain is vastly outweighed by the potential public health loss through inactivity etc. Ie questions were "Is cycle helmet legislation/promotion a public health benefit?"

Steve's (?) answer was just based on changes in absolute injuries/deaths of cyclists. Ie question of "Do helmet laws reduce cyclist injuries/deaths?" which is a very different matter.

[drossall]

Some good points made above. I would say that the speakers were both odd choices, although maybe it was hard to find better, as both could speak lucidly.

On the one hand, yes, you had an industry advocate. On the other, Ian Walker was presented as having originated the questions about helmet efficacy. However good he is as a speaker, that's simply rubbish; the earliest questions I'm aware of were raised in The Journal of Product Liability in 1988, and a five-second search of the BMJ archive shows the medical profession debating it from at least the early 1990s. The whole business around Thompson and Rivara, and the separate one of Dorothy Robinson's rebuttals of the statistical bases for Australian helmet laws, all happened a decade or more before Ian Walker's study. To be honest, I had never even thought of his study as primarily about helmets - it's about behaviour. Anyone who identified Ian as originating helmet questions just didn't do any research.

The statement that (by contrast with differences between helmet designs being an issue of small percentages) whether you wear a helmet is a 100% issue was just silly, as 100% would mean that helmet-wearing cyclists don't get head injuries.

And then we got into the real nonsense around the risk compensation issue, which the presenter seemed simply not to understand. Ian Walker's work was portrayed as showing only a small degree of difference in behaviour. The presenter seemed to fail completely to grasp two things:

• Across a large sample, a small difference can have an immeasurably greater net effect than a large difference across a small sample
• If risk compensation happens (and Walker's study supports the idea that it does), then there's nothing special about motorists, and we all do it

Thus, if it's true that drivers take even slightly less care, on average, in every one of the enormous number of overtakes of bikes that happens every year, the increased risk to cyclists is going to be very substantial compared with the difference that can be made on the (by comparison) tiny number of occasions when cyclists actually fall off and hit their heads. We're talking about the increased risk of being hit by a motor vehicle, for heaven's sake. What's more, and the enquirer apparently understood this when the presenter did not, it implies that I as a cyclist may equally take a tiny amount of additional risk, on every ride I take, which could easily lead to the one extra crash in my entire life-time that is really serious for me; this would thus dwarf the possible benefits of helmet wearing for me personally (I've never yet crashed in a helmet, so my personal benefit from helmet wearing is nil on any measure whatever).

It made a big difference to the overall impression that the first speaker got to respond to Walker, but not vice versa. In the formal debates I saw in my youth, that's why both sides always got a chance to respond. And, right at the start, it was disappointing that the only other countries mentioned were Australia and the US, when the Anglo-centric aberration of responding with helmets is part of the whole point. Finally, at the end, he quotes Spiegelhalter and Goldacre, yet entirely misses the main thrust of their point, which is that the statistical evidence is conflicting and has no clear outcome - this of course undermines the early part of the programme, which states the opposite.

Even though the programme did come out more balanced than many, where are BBC Verify when you want them?

[horizon]

I didn't listen to it but didn't miss it (if you see what I mean). As others have said, the evidence is very inconclusive so unless there is something new, it will be the same arguments rehashed.

What does concern me though is that the cycle helmet appears to be a fetish object for many people - not for cyclists (who must simply make a practical decision as to wear one or not) but for the general, mainly non-cycling public. Their obsession with helmets certainly deserves a well-researched radio programme of its own.

AIUI, their reasoning (such as it is) is as follows:

1. Riding a bicycle presents the possibility of being thrown off.
2. Being thrown from a cycle at speed might involve a severe blow to the head.
3. A severe blow to the head may damage the brain and its functions.
4. A cycle helmet may reduce the impact of the blow.
5. Therefore one must always wear a cycle helmet if cycling.

It is obvious to us (and even by the way I would have thought to most cyclists who do wear helmets) that even though superficially true, every stage of this reasoning is fraught with caveats, uncertainty and conflicting evidence (should one choose to consider them).

I can accept that many cyclists will just get on with their riding, helmet or not. They will have to make the decision as to whether any practical impediment is outweighed by the putative benefits. But that is different from people telling others that they should wear one. And that is where the BBC comes in (BTW, one thing I would say is that anyone who believes that wearing a helmet makes cycling safe shouldn't be cycling (most are not).

IMV where the BBC has really failed on this occasion though is to challenge the underlying reasoning on cycle helmets that I listed above. This is because it is a mode of reasoning that isn't restricted to cycle helmets but permeates lots of areas of life: simple black and white logic that appears to be the basis for sensible decision-making but is in fact in need of the much deeper questioning that most people simply won't do. And that means that our lives are poorer as a consequence.

[simonineaston]

Some interesting points made in this topic by folks who clearly feel strongly about the sort of advice we can receive via the broadcast media on the subject. I wonder - have any of us written to the BBC to let them know of our feelings about the programme episode? I think that would be worth doing and not too onerous - simply copy / paste into a text box.
https://www.bbc.co.uk/programmes/articl ... iced-bread

[mattheus]

I didn't listen to it but ...
...

IMV where the BBC has really failed on this occasion though is

okay ...

[De Sisti]

I didn't listen to it but didn't miss it (if you see what I mean).

No, not really.

[axel_knutt]

The majority of the population think risk compensation is barking mad,

The idea that people do not modify their behaviour according to the risk they perceive seems very odd to me.

Especially when there are so many obvious examples in front of everyone's noses. It's sad what a closed mind can do.

I was unimpressed by his describing the phenomenon of risk compensation as 'a philosophy', a term which implied that risk compensation is not something which can be analysed using the scientific method, but is instead something which some people choose to believe in like a religious faith.

It seems obvious that people are bending over backwards to avoid conducting studies like the 40 year old American M/C helmet study that Adams cites because they know there's a high probablility they'll get the answer they don't want. They could have repeated the study several times over and settled the issue in the last 40 years.

If risk compensation happens (and Walker's study supports the idea that it does), then there's nothing special about motorists, and we all do it

This.

it is a mode of reasoning that isn't restricted to cycle helmets but permeates lots of areas of life

At the root of it lies the patently false belief that risk is undesirable, and that the appetite for risk doesn't vary from person to person.

Some interesting points made in this topic by folks who clearly feel strongly about the sort of advice we can receive via the broadcast media on the subject. I wonder - have any of us written to the BBC to let them know of our feelings about the programme episode? I think that would be worth doing and not too onerous - simply copy / paste into a text box.
https://www.bbc.co.uk/programmes/articl ... iced-bread

I'll send them a link to this thread when I've finished here.

[Jdsk]

BBC programme in the Sliced Bread series: "Cycle Helmets":
https://www.bbc.co.uk/sounds/play/m001n21k

I've only listened to the second half and bits of the first half so far. There's a discussion with Walker: I'd always listen to what he has to say. And I totally agree about the importance of being very clear about the different questions. That's one of the key steps that would improve the discussion in this forum.

And the other steps are to stick to the other essentials of *evidence-based methods.

So when "risk compensation" is being discussed that would include referring to studies of whether it's occurring and to what extent in the setting of interest.

Without that it's only a possibility. I would refer to the assumption that it must be happening to any important extent as a dogma (rather than a philosophy).

Jonathan

* Being clear about the different questions is of course part of evidence-based methodology. But it was explicitly referred to in this programme and it's so important in this subject that I put it in the OP.