Highway Code revisions: helmet discussion

[Zulu Eleven]

Are you sure you want to cite such notoriously biased authors

Reminder, dismissing the authors as biased is what people do when they can’t disprove the data…

In other news, CTT entering 21st century: https://road.cc/content/news/helmets-li ... mbs-288415

[mattheus]

Are you sure you want to cite such notoriously biased authors

Reminder, dismissing the authors as biased is what people do when they can’t disprove the data…

Well no actually - I just read what many qualified statisticians and scientists have said on reviewing that paper.

How about you?

[Zulu Eleven]

Well no actually - I just read what many qualified statisticians and scientists have said on reviewing that paper.

How about you?

Then those ‘ qualified statisticians and scientists’ can follow the comment & editorial procedure in accordance with Cochrane guidelines - that is how science is done - the fact that no valid objections to the protocol resulting in withdrawal have come forward shows how little credence the hysterical anti-mask, oops, I mean anti-helmet brigade’s critique deserves.

I mean, no journal is perfect - Cochrane has indeed withdrawn studies in the past based on valid challenges… but your argument appears to be that in the established field of scientific research, one of the most respected sources and publishers of systemic research has - seemingly uniquely - disregarded both science and published editorial guidelines to support a fairly minor and in the grand scheme of things fairly inconsequential review of evidence regards bicycle helmets. Presumably at the behest of ‘big-helmet’ I suppose… or maybe in an effort to keep the lizard people safe from the effects of the chemtrails.

[Jdsk]

Please could this be continued in a thread in the Helmet forum. And I'll add a bit about the most recent Systematic Review.

Thanks

Jonathan

[Mike Sales]

Are you sure you want to cite such notoriously biased authors

Reminder, dismissing the authors as biased is what people do when they can’t disprove the data…

In other news, CTT entering 21st century: https://road.cc/content/news/helmets-li ... mbs-288415

So you would not want to decry Spiegelhalter and Goldacre when, in their BMJ article, they conclude that there is no evidence that helmets reduce casualties?
https://www.badscience.net/2013/12/bicy ... demiology/

They rather demolish the work of Thompson, Rivara, Thompson, and conclude that "The enduring popularity of helmets as a proposed major intervention for increased road safety may therefore lie not with their direct benefits—which seem too modest to capture compared with other strategies—but more with the cultural, psychological, and political aspects of popular debate around risk."

https://www.bmj.com/content/346/bmj.f38 ... eytype=ref

[Jdsk]

So you would not want to decry Spiegelhalter and Goldacre when, in their BMJ article, they conclude that there is no evidence that helmets reduce casualties?
https://www.badscience.net/2013/12/bicy ... demiology/

Where do they conclude that in that paper, please?

(It is an important paper that everyone should read.)

Thanks

Jonathan

[Zulu Eleven]

So you would not want to decry Spiegelhalter and Goldacre when, in their BMJ article, they conclude that there is no evidence that helmets reduce casualties?
https://www.badscience.net/2013/12/bicy ... demiology/

Where do they conclude that in that paper, please?

(It is an important paper that everyone should read.)

Thanks

Jonathan

It certainly bears little relevance to the question of whether a Helmet may 'reduce your risk of sustaining a head injury in certain circumstances'

Which is the statement made in the Highway Code.

Or even whether ‘Wearing a helmet dramatically reduces the risk of head and facial injuries for bicyclists involved in a crash,’ which was the conclusion of the Cochrane review.

[mjr]

Are you sure you want to cite such notoriously biased authors

Reminder, dismissing the authors as biased is what people do when they can’t disprove the data…

Reminder, Thompson Rivara Thompson's data had already been shown to be questionable and unreproducible.

Do you really have no problem with helmet-funded researchers giving their own work extra weight by including it in Cochrane reviews?

In other news, CTT entering 21st century: https://road.cc/content/news/helmets-li ... mbs-288415

There's a thread for that already. It was done for the novel reason of protecting the welfare of organisers, not riders!

[Pete Owens]

Are you sure you want to cite such notoriously biased authors

Reminder, dismissing the authors as biased is what people do when they can’t disprove the data…

But those authors have a long notorious history of pushing absurdly fanciful claims on the effectiveness of helmets, based on studies with extremely small and systematically biased samples. Their helmet advocacy long preceded their study.

Their oft quoted original study that made the 88% claim has been thoroughly debunked to the point that they even withdrew the claim themselves (and if they were remotely curious about their research, rather than seeking to confirm their biases, such an implausibly high figure should have rung alarm bells about their methodology rather than to be headlined). In a nutshell the data basically compared white kids covered by health insurance who had minor injuries riding in parks and were taken to the emergency room by their parents - with black kids without health insurance being whisked off in an ambulance after suffering major trauma following an RTA. Others have applied their methodology to their data set to produce equally high helmet effectiveness figures for preventing injuries to other parts of the body.

Since then there has been the opportunity to conduct large scale population based trials - before and after studies based on states that have legislated for compulsory helmet wearing. None of these has shown any significant change in the head injury rate for cyclists despite a huge jump in the amount of helmet wearing. The only significant finding in any of these studies was that such laws result in a suppression of cycling. If there was any significant effect (even a fairly modest one) one way or the other the that would show up in these studies. It doesn't so their isn't.

Now the point of a Cochrane review is to combine all the available data sets from studies into a particular intervention, but the authors systematically screened out these studies which didn't support their conclusions. Almost all the research they looked at was either conducted by themselves - or secondary research based on their data (effectively double counting).

[Mike Sales]

So you would not want to decry Spiegelhalter and Goldacre when, in their BMJ article, they conclude that there is no evidence that helmets reduce casualties?
https://www.badscience.net/2013/12/bicy ... demiology/

Where do they conclude that in that paper, please?

(It is an important paper that everyone should read.)

Thanks

Jonathan

Spiegelhalter and Goldacre say that case controlled studies have many methodological shortcomings.

This finding of “no benefit” is superficially hard to reconcile with case-control studies, many of which have shown that people wearing helmets are less likely to have a head injury. Such findings suggest that, for individuals, helmets confer a benefit. These studies, however, are vulnerable to many methodological shortcomings. If the controls are cyclists presenting with other injuries in the emergency department, then analyses are conditional on having an accident and therefore assume that wearing a helmet does not change the overall accident risk. There are also confounding variables that are generally unmeasured and perhaps even unmeasurable. People who choose to wear bicycle helmets will probably be different from those who ride without a helmet: they may be more cautious, for example, and so less likely to have a serious head injury, regardless of their helmets.

Rivara Thompson and Rivara rely on case controlled studies.

A case-control study of the effectiveness of bicycle safety helmets

Thompson, Rivara & Thompson. New England Journal of Medicine 1989, Vol 320 No 21 p1361-7.

Same data set used in this other paper by the same authors:
A case-control study on the effectiveness of bicycle safety helmets in preventing facial injury.
American Journal of Public Health, 1990; 80(12):1471-1474.

Effectiveness of bicycle safety helmets in preventing head injuries: a case-control study

Thompson DC, Rivara FP, Thompson RS. JAMA, 1996 Dec 25;276(24):1968-73

Their Cochrane Review uses their own work.

[Zulu Eleven]

[Do you really have no problem with helmet-funded researchers giving their own work extra weight by including it in Cochrane reviews?

Ah, “big helmet” rears its ugly and no doubt rotationally injured head again,

I guess that in a world where the entire field of scientific reviews had *never* had to encounter and deal with the complex issues of tobacco companies, oil companies or pharmaceutical manufacturers all funding research you might have a point…

[Zulu Eleven]

But those authors have a long notorious history of pushing absurdly fanciful claims on the effectiveness of helmets, based on studies with extremely small and systematically biased samples. Their helmet advocacy long preceded their study.

Yet, magically, still no valid challenge to the Cochrane review based upon either methodological failings or contrary results. It’s almost as if the anti-helmet brigade have so far entirely failed to garner a valid challenge based on the flaws they claim exist, or present it through the established and robust comment and editorial process

[Jdsk]

So you would not want to decry Spiegelhalter and Goldacre when, in their BMJ article, they conclude that there is no evidence that helmets reduce casualties?
https://www.badscience.net/2013/12/bicy ... demiology/

Where do they conclude that in that paper, please?

(It is an important paper that everyone should read.)

Spiegelhalter and Goldacre say that case controlled studies have many methodological shortcomings.

This finding of “no benefit” is superficially hard to reconcile with case-control studies, many of which have shown that people wearing helmets are less likely to have a head injury. Such findings suggest that, for individuals, helmets confer a benefit. These studies, however, are vulnerable to many methodological shortcomings. If the controls are cyclists presenting with other injuries in the emergency department, then analyses are conditional on having an accident and therefore assume that wearing a helmet does not change the overall accident risk. There are also confounding variables that are generally unmeasured and perhaps even unmeasurable. People who choose to wear bicycle helmets will probably be different from those who ride without a helmet: they may be more cautious, for example, and so less likely to have a serious head injury, regardless of their helmets.

Rivara Thompson and Rivara rely on case controlled studies.

A case-control study of the effectiveness of bicycle safety helmets

Thompson, Rivara & Thompson. New England Journal of Medicine 1989, Vol 320 No 21 p1361-7.

Same data set used in this other paper by the same authors:
A case-control study on the effectiveness of bicycle safety helmets in preventing facial injury.
American Journal of Public Health, 1990; 80(12):1471-1474.

Effectiveness of bicycle safety helmets in preventing head injuries: a case-control study

Thompson DC, Rivara FP, Thompson RS. JAMA, 1996 Dec 25;276(24):1968-73

Their Cochrane Review uses their own work.

You said that Speigelhalter and Goldacre in that article "conclude that there is no evidence that helmets reduce casualties". So I asked where. Your answer doesn't say where. "This finding of “no benefit”" isn't their conclusion, they're commenting on someone else's publication.

I'll try once more... where in that paper do they conclude "that there is no evidence that helmets reduce casualties"? Your words.

Thanks

Jonathan

[Mike Sales]

I'll try once more... where in that paper do they conclude "that there is no evidence that helmets reduce casualties"? Your words.

Thanks

Jonathan

I think that saying that the "direct benefits are too modest to capture, compared with other strategies" comes fairly close to saying that no evidence has been shown.
They clearly do not think that R,T&R have "captured" evidence of benefits.
I did not claim to be quoting their words.
Uncaptured benfits are not very good evidence!

[Pete Owens]

But those authors have a long notorious history of pushing absurdly fanciful claims on the effectiveness of helmets, based on studies with extremely small and systematically biased samples. Their helmet advocacy long preceded their study.

Yet, magically, still no valid challenge to the Cochrane review based upon either methodological failings or contrary results.

The challenge to their methodology is the systematic filtering out of the large volume of evidence that doesn't support their conclusions from the review. It is rather like Newcastle United claiming to be the top club in the premier league by analysing the results from the most recent 38 games in which they won.

I did explain this in the post you supposedly replying to, but you snipped it off.

Since you claim to be a fan of data. Please explain why the rate of head injuries INCREASED for cyclists following helmet compulsion in New South Wales.