Masks today, helmets tomorrow?

For all discussions about this "lively" subject. All topics that are substantially about helmet usage will be moved here.
Jdsk
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Re: Masks today, helmets tomorrow?

Postby Jdsk » 16 Jul 2020, 1:55pm

I don't understand the question. Doctors prescribe drugs to patients and some of those drugs cause harm to and some cause the death of those patients.

An evidence-based approach allows that to be quantified and the right balances struck.

Jonathan

Mike Sales
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Re: Masks today, helmets tomorrow?

Postby Mike Sales » 16 Jul 2020, 2:03pm

Jdsk wrote:I don't understand the question. Doctors prescribe drugs to patients and some of those drugs cause harm to and some cause the death of those patients.

An evidence-based approach allows that to be quantified and the right balances struck.

Jonathan


I'm sorry. I was not clear.
Patient A is given a drug which my or may not harm them. I think you refer to this case.
I suggest that if patient A is treated with a drug which may save them but which may kill patient B there is an ethical problem.

Jdsk
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Re: Masks today, helmets tomorrow?

Postby Jdsk » 16 Jul 2020, 2:10pm

Totally agree.

In healthcare there might be some examples where there's direct harm to Patient B, but there are many where it's indirect such as antibiotics and resistance, and one where it's universal: the allocation of resources.

But I don't see the need for an analogy from another sector: there's obviously an ethical problem with any activity that causes the death of anybody. Has anyone ever denied that?

Jonathan

PS: Have I found the right papers?

Mike Sales
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Re: Masks today, helmets tomorrow?

Postby Mike Sales » 16 Jul 2020, 2:37pm

Jdsk wrote:Totally agree.

In healthcare there might be some examples where there's direct harm to Patient B, but there are many where it's indirect such as antibiotics and resistance, and one where it's universal: the allocation of resources.

But I don't see the need for an analogy from another sector: there's obviously an ethical problem with any activity that causes the death of anybody. Has anyone ever denied that?

Jonathan

PS: Have I found the right papers?


I was thinking that it was a clumsy analogy, and not very useful.
The problem with belts is that they have been mandated, as a public health intervention at the expense of some road users, for the putative advantage of others.
This problem is not something publically discussed, quite the contrary.
Perhaps another parallel might contribute.
Motor vehicles put out various pollutants, which have been getting publicity lately.
If they were fitted with efficient filters, so that those in them could breath healthy air, but those outside breathed the pollution, would that be reasonable?
Of course, such a set up would not make things worse for those on foot or two wheels, so not a complete parallel.

In any case, mandating a measure which makes the vulnerable even less safe seems to me wrong.

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pjclinch
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Re: Masks today, helmets tomorrow?

Postby pjclinch » 16 Jul 2020, 2:58pm

Both Death on the Streets and Risk are available as free PDF downloads

Risk is at http://www.john-adams.co.uk/wp-content/uploads/2017/01/RISK-BOOK.pdf
Death on the Streets is at https://roaddangerreductionforum.files.wordpress.com/2011/06/deathonthestreets1992-3.pdf

Risk in particular shows how Real Life diverges from nice neat measurements and certainties by involving people, who really mess things up.

Pete.
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Jdsk
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Re: Masks today, helmets tomorrow?

Postby Jdsk » 16 Jul 2020, 3:40pm

Thanks, I hadn't seen a copy of Death on the Streets before.

Jonathan

Jdsk
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Re: Masks today, helmets tomorrow?

Postby Jdsk » 16 Jul 2020, 3:46pm

Mike Sales wrote:Regarding evidence based policy making, the episode of the Isles Report is interesting.

Adams writes:

However within the Department of Transport, the promoters of the seat belt bill, my study had raised concerns. The Department commissioned a critique of my report by J E Isles. His report examined evidence from eight European countries (a subset of the 18 examined in my report) that had passed seat belt laws. He concluded that a law making the wearing of seat belts compulsory “has not led to a detectable change in road death rates”. For promoters of the bill this was an inconvenient truth. The Isles report was dated April 1981, more than three months before the parliamentary debate that led to the passage of the legislation. But it was suppressed. It was not published, and was not allowed to inform that debate. The Isles Report did not see the light of day until its existence was disclosed by New Scientist in an article published on 7 February 1985 – more than three years too late.

In the 1981 Parliamentary debate opponents of the law described my report variously as “bogus”, “riddled with inaccuracies”, “eccentric”, “preposterous”, “spurious”, and “wrong”. One supporter of the law (Austin Mitchell MP) described my report as “the only one that the hon. and learned Gentleman [Ivan Lawrence MP] can dredge up.” The Secretary of State for Transport in his contribution to the debate described my risk compensation hypothesis as “dubious and not proven”, but made no mention of his own department’s study whose conclusions supported mine. And my principal champion (Ivan Lawrence) described my findings as “astonishing and unexpected”. Such, at the time was the response to explanations of road accident statistics that invoked the risk compensation hypothesis.


http://www.john-adams.co.uk/2007/01/04/seat-belt-legislation-and-the-isles-report/

Robert Davis, on page 80 of Death on the Streets quotes the Isles Report.

claims for seat belt law effects were exaggerated, and that the likely effects in Britain would be either minimal or negative benefits for car users and an increase in deaths and injuries for people outside cars


The study (of the effects after the law had been passed) to which I have already referred, bore out the finding that a seat belt law would cost the lives of vulnerable road users.
This study was published in Significance, the journal of The Royal Statistical Society and was written by three seat belt proponents who were also members of the Parliamentary Advisory Committee on Traffic Safety.

They say “the clear reduction in death and injury to car occupants is appreciably offset by extra deaths among pedestrians and cyclists.”
.

http://www.john-adams.co.uk/2013/03/24/the-biggest-lie/

The idea that people's behaviour is unaffected by how safe they feel seems, to say the least, counterintuitive.

Two professors of statistics, Durbin and Harvey, were asked by the DoT to look at the question.

They concluded:-

The large estimated increases of pedestrian and cyclist fatalities suggest the possibilty of some change in driving behaviour by some drivers of cars and light goods vehicles after the introduction of the seat belt law.


It is, of course, impossible to examine the mental processes of all these drivers, but the evidence from their driving is clear.

I'm not sure there's much point in my asking again whether the papers I've found are the ones which you cited. Would it be OK if I worked on the assumption that they are the right ones but that you aren't familiar with them so that you can check?

That way we could move on to discussing their contents.

Thanks

Jonathan

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pjclinch
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Re: Masks today, helmets tomorrow?

Postby pjclinch » 16 Jul 2020, 4:44pm

Jdsk wrote:That way we could move on to discussing their contents.


To be honest I've mainly given up going through papers, because I reached the point where the Big Learning Point of "it's all a horrible mess with lots of heat and little light" struck home (I started looking in detail about the turn of the century, I stopped a few years back).

To quote Goldacre's commentary on his co-editorial,
Here’s an editorial I wrote in the British Medical Journal with David Spiegelhalter, about the complex contradictory mess of evidence on the impact of bicycle helmets. Like most places where there’s controversy and disagreement, this is a great opportunity to walk through the benefits and shortcomings of different epidemiological techniques, from case control studies to modelling.


Lots of people have been looking at this very hard for decades, including lots of people who really know what they're doing a lot better than I do (I'm in science, but support and some basic teaching rather than research, and my main insight in to stats is knowing my considerable limits), and nobody has really found any smoking guns in that time. I don't think I'm going to find one either.

My main interest in "the helmet debate" is trying to convince people there are better things they could be spending their energy on than contributing to our society's reverence for something that doesn't demonstrably do much except create flame wars. In other words, for people that think there is clear evidence for us to actively encourage/require helmets/no helmets as a policy that the state of the evidence is too poor to support that.

If someone can iron out the issues that will probably involve creation of genuinely useful tools for a myriad of awkward subjects so good on them for doing the work, but I think all we can really achieve here is knocking more holes in stuff which is already pretty shaky. The bottom line of "not proven" will still be there.
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Jdsk
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Re: Masks today, helmets tomorrow?

Postby Jdsk » 16 Jul 2020, 4:52pm

Agreed: when the evidence is weak we should say so.

Recent posts in this thread followed:

Mike Sales wrote:The seat belt wearer protects themself at the expense of those who suffer their increased risk taking.


The second part of that, as worded, is a strong assertion. I don't think that there is correspondingly strong supporting evidence.

Jonathan

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pjclinch
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Re: Masks today, helmets tomorrow?

Postby pjclinch » 16 Jul 2020, 6:23pm

Jdsk wrote:Agreed: when the evidence is weak we should say so.

Recent posts in this thread followed:

Mike Sales wrote:The seat belt wearer protects themself at the expense of those who suffer their increased risk taking.


The second part of that, as worded, is a strong assertion. I don't think that there is correspondingly strong supporting evidence.


The main evidence was a clear jump in reported casualties amongst vulnerable road users following seat belt legislation (and commensurately greater use of safety equipment).

Maybe that was influenced by, say, evidential breath testing brought in at the same time but that is a bit of a stretch...

There really isn't much doubt that risk compensation exists, the main problems come down to the issues of individuals vs. "average people", i.e., it's unpredictable in specific cases. But I don't see it as particularly contentious that introducing "improved safety" results in compensating behaviour, and in the case of motor vehicles that will be bad news for those beyond the scope of the intervention.

What's the obvious hole in using the jump in casualties?

Pete.
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Jdsk
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Re: Masks today, helmets tomorrow?

Postby Jdsk » 16 Jul 2020, 6:25pm

pjclinch wrote:The main evidence was a clear jump in reported casualties amongst vulnerable road users following seat belt legislation (and commensurately greater use of safety equipment).

Maybe that was influenced by, say, evidential breath testing brought in at the same time but that is a bit of a stretch...

...

What's the obvious hole in using the jump in casualties?

Which datasets or original studies are you using to identify that jump, please?

Is it based on Harvey and Durbin (1986) as above?

Thanks

Jonathan

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pjclinch
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Re: Masks today, helmets tomorrow?

Postby pjclinch » 16 Jul 2020, 7:16pm

Jdsk wrote:Which datasets or original studies are you using to identify that jump, please?


You'll have to forgive my lack of rigour in not seeking out the original data reported on by Davis & Adams, but if you want a set of road accident figures for the UK as a whole, year to year, I imagine something like STATS19 is a typical first port of call.

Pete.
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Tangled Metal
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Re: Masks today, helmets tomorrow?

Postby Tangled Metal » 16 Jul 2020, 10:48pm

Jdsk wrote:
Tangled Metal wrote:What would happen if the doctors treating boxers asked if they were wearing a helmet? A sport where damage to your brain is part of the appeal to its fans doesn't get the same calls for helmet wearing that cycling does.

From doctors? Are you aware of the enormous opposition to boxing from many doctors and the campaigning to stop it? For example the World Medical Association's position:
https://www.wma.net/policies-post/wma-statement-on-boxing/
which includes:
"The WMA believes that boxing is qualitatively different from other sports because of the injuries it causes and that it should be banned."
"Until a full ban is achieved the WMA urges that the following measures be implemented... Personal protective equipment recommendations (such as size and weight of gloves, head gear and gum shields) should take into consideration medical recommendations."

Jonathan

Of course but boxing still has doctors fulfilling various roles within boxing from deciding if boxers are fit to box to treating afterwards. The latter I can accept but the former is condemning the fit boxers to potential and likely harm. I wonder if there's anything the medical profession involved in boxing can do but don't that could limit harm. I'm afraid I'm opposed to this barbaric entertainment I wish more could be done to stop it.

Jdsk
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Re: Masks today, helmets tomorrow?

Postby Jdsk » 16 Jul 2020, 10:52pm

Tangled Metal wrote: I wonder if there's anything the medical profession involved in boxing can do but don't that could limit harm.

Have you had a chance to read the WMA statement?

Jonathan

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Cunobelin
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Re: Masks today, helmets tomorrow?

Postby Cunobelin » 17 Jul 2020, 6:55am

Marcus Aurelius wrote:I think the government should have used the original outbreak to enforce cycle helmets. It stands to reason. You have unusually high demand on the NHS resources, you don’t want added pressure from cyclists with the inevitable head injuries sustained if they have an accident without a lid, so that’s a great excuse to make compulsory lid wearing whilst cycling ( on a road at least ) law.


As always, the facts are not in favour. Cohort studies show many reasons for head injury admissions, and cycling is one of the lowest. If the interest is really in the reduction of head injuries and pressure on the NHS, then Pedestrian Helmets are the way to go

But of course that will be silly!