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#121
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The BMA Recycle BeHIT Bull****
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 |
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#122
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The BMA Recycle BeHIT Bull****
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/ |
#123
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The BMA Recycle BeHIT Bull****
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/ |
#124
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The BMA Recycle BeHIT Bull****
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/ |
#125
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The BMA Recycle BeHIT Bull****
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 |
#126
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The BMA Recycle BeHIT Bull****
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/ |
#127
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The BMA Recycle BeHIT Bull****
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 |
#128
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The BMA Recycle BeHIT Bull****
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/ |
#129
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The BMA Recycle BeHIT Bull****
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 |
#130
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The BMA Recycle BeHIT Bull****
"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. |
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