The BMA Promote Safer Cycling

On 23 Apr, 15:48, Mike Clark wrote:
In message
* * * * * Toom Tabard wrote:

[snip]







Not necessarily. You may not have the statistical proof, but the
empirical experience and knowledge of the practitioners in the
particular area can be strongly indicative of the true effect and
point to the flaws, and the reasons for them, in the statistical
analysis. When reality seems at variance with the numbers, it is
frequently the numbers which are flawed. There a legions of social,
health and safety studies where concentration on the numbers followng
the issues receiving concentrated attention, result in problems with
comparison with earlier data which wasn't collected under the same
spotlight, but where the empirical experience of practitioners not
involved in the statistical studies can give some, possibly the best,
evidence of the true effect.

Toom

Presumably you can cite some specific examples to substantiate your
generalisations above?


I certainly can, but you state you are a PhD, and a Reader, and in a
medical discipline. Doesn't a PhD still involve finding things out
for yourself. Most of the PhD students in my research lab seemed
capable of this.

You must, for many years have been tripping over copious specific
examples illustrating what I've said. Didn't you notice them?I didn't
know what I said was contentious. It certainly shouldn't be to any
competent and aware researcher.

Toom

On 23 Apr, 15:57, Peter Clinch wrote:
Mike Clark wrote:
In message
* * * * * Toom Tabard wrote:

[snip]
Not necessarily. You may not have the statistical proof, but the
empirical experience and knowledge of the practitioners in the
particular area can be strongly indicative of the true effect and
point to the flaws, and the reasons for them, in the statistical
analysis. When reality seems at variance with the numbers, it is
frequently the numbers which are flawed. There a legions of social,
health and safety studies where concentration on the numbers followng
the issues receiving concentrated attention, result in problems with
comparison with earlier data which wasn't collected under the same
spotlight, but where the empirical experience of practitioners not
involved in the statistical studies can give some, possibly the best,
evidence of the true effect.
Presumably you can cite some specific examples to substantiate your
generalisations above?

Preferably that take into account the lack of proper control data in a
comparative head injury scenario, and where the practitioners have been
bombarded with years of unsubstantiated claims (the infamous 85% figure
from TRT '89 in particular) about the effectiveness of the proposed
intervention to bias their opinion.

Pete.
--
Peter Clinch * * * * * * * * * *Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 * Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 * * * * * * *Dundee DD1 9SY Scotland UK
net * *http://www.dundee.ac.uk/~pjclinch/- Hide quoted text -


------------------------------------------------------------------------

On 21 Apr, 21:25, Peter Clinch wrote:

But since he's established he really /can't/ tell the
difference between his opinions and fact I really ought to give up
and stop muddying urc's waters further: he's given himself enough
rope, tied the noose and jumped off the stool as far as his
pronouncements on helmets go.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/

On 23 Apr, 16:04, Peter Clinch wrote:
Peter Clinch wrote:
Preferably that take into account the lack of proper control data in a
comparative head injury scenario, and where the practitioners have been
bombarded with years of unsubstantiated claims (the infamous 85% figure
from TRT '89 in particular) about the effectiveness of the proposed
intervention to bias their opinion.

Oh, and also accounts for the fact that the practitioners will only see
the end result of the accident, and are unlikely to take any account of
the degree to which the proposed intervention may have caused it to
happen in the first place.

Pete.
--
Peter Clinch * * * * * * * * * *Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 * Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 * * * * * * *Dundee DD1 9SY Scotland UK
net * *http://www.dundee.ac.uk/~pjclinch/

-----------------------------------------------------------------------------

On 21 Apr, 21:25, Peter Clinch wrote:

But since he's established he really /can't/ tell the
difference between his opinions and fact I really ought to give up
and stop muddying urc's waters further: he's given himself enough
rope, tied the noose and jumped off the stool as far as his
pronouncements on helmets go.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/

In message
Toom Tabard wrote:

On 23 Apr, 15:48, Mike Clark wrote:
In message
* * * * * Toom Tabard wrote:

[snip]

Not necessarily. You may not have the statistical proof, but the
empirical experience and knowledge of the practitioners in the
particular area can be strongly indicative of the true effect and
point to the flaws, and the reasons for them, in the statistical
analysis. When reality seems at variance with the numbers, it is
frequently the numbers which are flawed. There a legions of
social, health and safety studies where concentration on the
numbers followng the issues receiving concentrated attention,
result in problems with comparison with earlier data which wasn't
collected under the same spotlight, but where the empirical
experience of practitioners not involved in the statistical
studies can give some, possibly the best, evidence of the true
effect.

Toom

Presumably you can cite some specific examples to substantiate your
generalisations above?


I certainly can, but you state you are a PhD, and a Reader, and in a
medical discipline. Doesn't a PhD still involve finding things out
for yourself. Most of the PhD students in my research lab seemed
capable of this.

As well as conducting ones own research a PhD should also teach you to
analyse critically opinions expressed by others, especially where there
seems to be a lack of evidence presented to substantiate those opinions.


You must, for many years have been tripping over copious specific
examples illustrating what I've said. Didn't you notice them?

Yes I've seen a lot of examples of empirical based medical treatments
some of which have later stood up to critical evidence based analysis
and others which have not. The problem is that all this allows me to
conclude is that sometimes empirical observations and evidence based
studies concur, and sometimes they don't. When they don't concur
sometimes it is because of a flaw in the evidence based studies and
sometimes because of misguided trust in empiricism. Ultimately if the
answer really is important to know, then the best thing to do is usually
to go away and design a better study.

I didn't know what I said was contentious. It certainly shouldn't be
to any competent and aware researcher.

Toom

It wasn't so much contentious as uninformative with regard to the topic
under debate. I was hoping that you could point me to where the
empirical experience and knowledge of practitioners in the field of
bicycle helmet usage points to where the flaws in the statistical
analysis of the data on overall injury rates are?

Mike
--
M.R. Clark PhD, Reader in Therapeutic and Molecular Immunology
Cambridge University, Department of Pathology
Tennis Court Road, Cambridge CB2 1QP
Tel +44 (0)1223 333705 Web http://www.path.cam.ac.uk/~mrc7/

On 24 Apr, 12:34, Mike Clark wrote:

It wasn't so much contentious as uninformative with regard to the topic
under debate. I was hoping that you could point me to where the
empirical experience and knowledge of practitioners in the field of
bicycle helmet usage points to where the flaws in the statistical
analysis of the data on overall injury rates are?


That would be a pointless exercise on this newsgroup. Having surveyed
in detail some of the associated 'helmet' websites where some studies
are presented, the sites are a farrago of twisting prejudice, where
any any research which finds helmets beneficial is dismissed as
partisan and biased, and then attacked and interpreted with cod
science and specious reasoning, and then twisted with statistical
ignorance. Research which does not support beneficial effects helmets
is seemingly not subject to the same standards of (mis)interpretation.

My remarks on the topic stand as they are, as an indication of where
the real explanation for genuine anomalies can lie.

It would be pointless to make any points on real studies and actual
statistics since it merely stirs up a hornet's nest from our resident
******s.

Toom

In message you wrote:

On 24 Apr, 12:34, Mike Clark wrote:

It wasn't so much contentious as uninformative with regard to the topic
under debate. I was hoping that you could point me to where the
empirical experience and knowledge of practitioners in the field of
bicycle helmet usage points to where the flaws in the statistical
analysis of the data on overall injury rates are?


That would be a pointless exercise on this newsgroup.

Well you could always email me directly.

Having surveyed in detail some of the associated 'helmet' websites
where some studies are presented, the sites are a farrago of twisting
prejudice, where any any research which finds helmets beneficial is
dismissed as partisan and biased, and then attacked and interpreted
with cod science and specious reasoning, and then twisted with
statistical ignorance.

Since it seems from your comments that you may be a laboratory trained
scientist you could always do what I do, which is to go to the source
journals and see exactly what has been published on the subject.

Research which does not support beneficial effects helmets is
seemingly not subject to the same standards of (mis)interpretation.

My conclusion is that there is a degree of misrepresentation and also
misinterpretation on both sides of the fence.


My remarks on the topic stand as they are, as an indication of where
the real explanation for genuine anomalies can lie.

But since you acknowledge in your statement that there are "genuine
anomalies" and have also chosen to use the word "can", that leaves open
some doubt as to whether your remarks do point to the true explanation.


It would be pointless to make any points on real studies and actual
statistics since it merely stirs up a hornet's nest from our resident
******s.

Toom

It seems to me then that you give up too easily. Science is often hard
work and usually requires dedication to succeed. However science also
tends to rely on testing the hypothesies with evidence, and if there are
anomalies it is usually necessary to explain them away with alternative
and better controlled tests, or overcome with a greater weight of
evidence.

Mike
--
M.R. Clark PhD, Reader in Therapeutic and Molecular Immunology
Cambridge University, Department of Pathology
Tennis Court Road, Cambridge CB2 1QP
Tel +44 (0)1223 333705 Web http://www.path.cam.ac.uk/~mrc7/

On 24 Apr, 14:52, Mike Clark wrote:
In message you wrote:

On 24 Apr, 12:34, Mike Clark wrote:

It wasn't so much contentious as uninformative with regard to the topic
under debate. I was hoping that you could point me to where the
empirical experience and knowledge of practitioners in the field of
bicycle helmet usage points to where the flaws in the statistical
analysis of the data on overall injury rates are?

That would be a pointless exercise on this newsgroup.

Well you could always email me directly.

Having surveyed in detail some of the associated 'helmet' websites
where some *studies are presented, the sites are a farrago of twisting
prejudice, where any any research which finds helmets beneficial is
dismissed as partisan and biased, and then attacked and interpreted
with cod science and specious reasoning, *and then twisted with
statistical ignorance.

Since it seems from your comments that you may be a laboratory trained
scientist you could always do what I do, which is to go to the source
journals and see exactly what has been published on the subject.

Research which does not support beneficial effects helmets is
seemingly not subject to the same standards of (mis)interpretation.

My conclusion is that there is a degree of misrepresentation and also
misinterpretation on both sides of the fence.



My remarks on the topic stand as they are, as an indication of where
the real explanation for genuine anomalies can lie.

But since you acknowledge in your statement that there are "genuine
anomalies" and have also chosen to use the word "can", that leaves open
some doubt as to whether your remarks do point to the true explanation.



It would be pointless to make any points on real studies and actual
statistics since it merely stirs up a hornet's nest from our resident
******s.

Toom

It seems to me then that you give up too easily. Science is often hard
work and usually requires dedication to succeed. However science also
tends to rely on testing the hypothesies with evidence, and if there are
anomalies it is usually necessary to explain them away with alternative
and better controlled tests, or overcome with a greater weight of
evidence.

Mike
--
M.R. Clark PhD, *Reader in Therapeutic and Molecular Immunology
Cambridge University, Department of Pathology
Tennis Court Road, Cambridge CB2 1QP
Tel +44 (0)1223 333705 * *Web *http://www.path.cam.ac.uk/~mrc7/

Yes, I have looked at the sources of many papers as well as the
'revised' interpretations in websites associated with some of our
contributors. That is within a wider context of several decades of
experience, work, study and personal interest which just happens to
have covered road accidents, road safety, science, technology,
research and statistics. All I have said on this group is that I'm
satisfied that cycle helmets provide substantial advantages in
preventing or mitigating the effects of injury, that the benefits are
not restricted to low speed accidents, or certain particular
categories of accident.

That, in my experience, is also the view of most - neurosurgeons,
paramedics, police, accident investigators and road safety experts -
who have been exposed the real world situation in detail, and forms
the basis for the official view and recommendations, in my experience
presented in good faith however much others regard the as some health
and safety plot by zealots. It is considerably more persuasive than
the opinion of cyclists who have read a few research papers by
researchers using necessarily incomplete data in surveys 'designed' by
available second-hand data and imprecise collection procedures. It is
not possible or ethical to have a large perfectly designed, double-
blind trial of the efficacy of cycle helmets in real accidents, and I
don't get involved in the huffing and puffing about the existing
research papers and statistics. Many have flaws from necessity,
carelessness, misinterpretation, etc.

If anyone thinks my views and advice are worthless then that is a
matter of disinterest to me. If they want substantiation by my arguing
with bald men over their theoretical statistical combs, then they
won't get it.

Toom

In message
Toom Tabard wrote:

On 24 Apr, 14:52, Mike Clark wrote:
In message you wrote:

On 24 Apr, 12:34, Mike Clark wrote:

It wasn't so much contentious as uninformative with regard to the topic
under debate. I was hoping that you could point me to where the
empirical experience and knowledge of practitioners in the field of
bicycle helmet usage points to where the flaws in the statistical
analysis of the data on overall injury rates are?

That would be a pointless exercise on this newsgroup.

Well you could always email me directly.

Having surveyed in detail some of the associated 'helmet' websites
where some *studies are presented, the sites are a farrago of twisting
prejudice, where any any research which finds helmets beneficial is
dismissed as partisan and biased, and then attacked and interpreted
with cod science and specious reasoning, *and then twisted with
statistical ignorance.

Since it seems from your comments that you may be a laboratory trained
scientist you could always do what I do, which is to go to the source
journals and see exactly what has been published on the subject.

Research which does not support beneficial effects helmets is
seemingly not subject to the same standards of (mis)interpretation.

My conclusion is that there is a degree of misrepresentation and also
misinterpretation on both sides of the fence.



My remarks on the topic stand as they are, as an indication of where
the real explanation for genuine anomalies can lie.

But since you acknowledge in your statement that there are "genuine
anomalies" and have also chosen to use the word "can", that leaves open
some doubt as to whether your remarks do point to the true explanation.



It would be pointless to make any points on real studies and actual
statistics since it merely stirs up a hornet's nest from our resident
******s.

Toom

It seems to me then that you give up too easily. Science is often hard
work and usually requires dedication to succeed. However science also
tends to rely on testing the hypothesies with evidence, and if there are
anomalies it is usually necessary to explain them away with alternative
and better controlled tests, or overcome with a greater weight of
evidence.

Mike
--
M.R. Clark PhD, *Reader in Therapeutic and Molecular Immunology
Cambridge University, Department of Pathology
Tennis Court Road, Cambridge CB2 1QP
Tel +44 (0)1223 333705 * *Web *http://www.path.cam.ac.uk/~mrc7/

Yes, I have looked at the sources of many papers as well as the
'revised' interpretations in websites associated with some of our
contributors. That is within a wider context of several decades of
experience, work, study and personal interest which just happens to
have covered road accidents, road safety, science, technology,
research and statistics. All I have said on this group is that I'm
satisfied that cycle helmets provide substantial advantages in
preventing or mitigating the effects of injury, that the benefits are
not restricted to low speed accidents, or certain particular
categories of accident.

That, in my experience, is also the view of most - neurosurgeons,
paramedics, police, accident investigators and road safety experts -
who have been exposed the real world situation in detail, and forms
the basis for the official view and recommendations, in my experience
presented in good faith however much others regard the as some health
and safety plot by zealots. It is considerably more persuasive than
the opinion of cyclists who have read a few research papers by
researchers using necessarily incomplete data in surveys 'designed' by
available second-hand data and imprecise collection procedures. It is
not possible or ethical to have a large perfectly designed, double-
blind trial of the efficacy of cycle helmets in real accidents, and I
don't get involved in the huffing and puffing about the existing
research papers and statistics. Many have flaws from necessity,
carelessness, misinterpretation, etc.

If anyone thinks my views and advice are worthless then that is a
matter of disinterest to me. If they want substantiation by my arguing
with bald men over their theoretical statistical combs, then they
won't get it.

Toom

Fair enough I understand your view. In my case I started out as an early
advocate for the wearing of cycle helmets. In the late 70s and early 80s
I usually found myself in a helmet wearing minority trying to convince
others of the benefits of wearing a cycle helmet. I also brought to
peoples attention the case controlled studies which seemed to show the
advantages of wearing a helmet.

However over time I started to look at the totality of all the evidence
both from case controlled studies and also from population studies. I
also became more aware of data associated with risk compensation. Indeed
my personal participation in sports such as rock climbing,
mountaineering and skiing demonstrated to me graphically that people
really do modify their behaviour in response to their own perceptions of
the risks, myself included. I also realised that peoples perceptions of
risk rarely reflected an accurate understanding of the probability of
any given risk.

Thus when I appreciated that there were indeed genuine anomalies in the
data providing evidence for the benefits of wearing a helmet I became
more sceptical.

My current position is that I remain unconvinced that cycle helmets
provide any substantial benefit for many forms of cycling, although I
wouldn't dismiss the possibility of there being an underlying small
benefit, particularly in some forms of cycling. Certainly on a cost
benefit analysis it seems strange to me to over emphasise the importance
of one risk, such as head injuries when cycling, and yet not to
appreciate the evidence that the risks of head injuries in many other
every day circumstances are likely to be much higher (such as when
walking along streets and roads, descending stairs, using ladders, or
taking a bath or shower, or returning home from the pub after a few
beers). Do I consider it an acceptable risk to undertake these other
activities without wearing helmet? Yes. Which is why I also now consider
it acceptable for people to choose to cycle without wearing a helmet.

Mike
--
M.R. Clark PhD, Reader in Therapeutic and Molecular Immunology
Cambridge University, Department of Pathology
Tennis Court Road, Cambridge CB2 1QP
Tel +44 (0)1223 333705 Web http://www.path.cam.ac.uk/~mrc7/

On 24 Apr, 17:46, Mike Clark wrote:

Fair enough I understand your view. In my case I started out as an early
advocate for the wearing of cycle helmets. In the late 70s and early 80s
I usually found myself in a helmet wearing minority trying to convince
others of the benefits of wearing a cycle helmet. I also brought to
peoples attention the case controlled studies which seemed to show the
advantages of wearing a helmet.

However over time I started to look at the totality of all the evidence
both from case controlled studies and also from population studies. I
also became more aware of data associated with risk compensation. Indeed
my personal participation in sports such as rock climbing,
mountaineering and skiing demonstrated to me graphically that people
really do modify their behaviour in response to their own perceptions of
the risks, myself included. I also realised that peoples perceptions of
risk rarely reflected an accurate understanding of the probability of
any given risk.

Thus when I appreciated that there were indeed genuine anomalies in the
data providing evidence for the benefits of wearing a helmet I became
more sceptical.

My current position is that I remain unconvinced that cycle helmets
provide any substantial benefit for many forms of cycling, although I
wouldn't dismiss the possibility of there being an underlying small
benefit, particularly in some forms of cycling. Certainly on a cost
benefit analysis it seems strange to me to over emphasise the importance
of one risk, such as head injuries when cycling, and yet not to
appreciate the evidence that the risks of head injuries in many other
every day circumstances are likely to be much higher (such as when
walking along streets and roads, descending stairs, using ladders, or
taking a bath or shower, or returning home from the pub after a few
beers). Do I consider it an acceptable risk to undertake these other
activities without wearing helmet? Yes. Which is why I also now consider
it acceptable for people to choose to cycle without wearing a helmet.

Mike

Thanks for that info, and I understand and appreciate your perception
and views. It does indeed ultimately boil down to individual choice. I
would, however, qualify that by saying that new or inexperienced
riders, particularly young ones, would perhaps be best advised to use
a helmet until they feel (or are old enough) that they can make that
judgement. As with learning to drive, there is much that you learn in
the first couple of years about road risks and how to spot and deal
with them, and there is an element of luck in completing that
experience without actual injury.

I'm aware of the effects of risk compensation - there are activities I
undertake for my own enjoyment where I choose and accept the risks. I
regard road use as a necessity where it is not worth taking undue
risk, and where much of what can happen depends on the actions of
others, and, from experience, both personally and professional, I'm
quite prepared to use any reasonable precautions to get safely from A
to B. Whilst it may be my attitudes to road use minimise my own risk
compensation, it helps to be aware of those who may be more regardless
of their own and my safety and to make extra allowance for this. So
far, so good, but then I can't prove why, and there is always the
occasional black swan on or off the road, as I recently reflected when
falling from a stepladder (without a helmet).

Toom

"Toom Tabard" wrote in message
...

I'm aware of the effects of risk compensation

The main benefit of wearing a helmet that often seems to be overlooked is
that it helps the wearer to ride faster and take more chances. Cornering can
be done faster, braking done later etc. and an overall feeling of euphoria
can accompany the feeling of being indestructible. Knee and elbow pads can
also help, gloves are essential for this.