Helmets reduce bicycle-related head and facial injuries
JMS
http://www.ncbi.nlm.nih.gov/pubmed/10796827
From the Cochrane Database Syst Rev.
(The Cochrane Collaboration is an international, independent,
not-for-profit organisation of over 27,000 contributors from more than
100 countries, dedicated to making up-to-date, accurate information
about the effects of health care readily available worldwide.)
Helmets for preventing head and facial injuries in bicyclists.
Abstract
BACKGROUND: Each year, in the United states, approximately 900 persons
die from injuries due to bicycle crashes and over 500,000 persons are
treated in emergency departments. Head injury is by far the greatest
risk posed to bicyclists, comprising one-third of emergency department
visits, two-thirds of hospital admissions, and three-fourths of
deaths. Facial injuries to cyclists occur at a rate nearly identical
to that of head injuries. Although it makes inherent sense that
helmets would be protective against head injury, establishing the
real-world effectiveness of helmets is important. A number of
case-control studies have been conducted demonstrating the
effectiveness of bicycle helmets. Because of the magnitude of the
problem and the potential effectiveness of bicycle helmets, the
objective of this review is to determine whether bicycle helmets
reduce head, brain and facial injury for bicyclists of all ages
involved in a bicycle crash or fall.
OBJECTIVES: To determine whether bicycle helmets reduce head, brain
and facial injury for bicyclists of all ages involved in a bicycle
crash or fall.
SEARCH STRATEGY: We searched The Cochrane Controlled Trials Register,
MEDLINE, EMBASE, Sport, ERIC, NTIS, Expanded Academic Index, CINAHL,
PsycINFO, Occupational Safety and Health, and Dissertations Abstracts.
We checked reference lists of past reviews and review articles,
studies from government agencies in the United States, Europe and
Australia, and contacted colleagues from the International Society for
Child and Adolescent Injury Prevention, World Injury Network, CDC
funded Injury Control and Research Centers, and staff in injury
research agencies around the world.
SELECTION CRITERIA: Controlled studies that evaluated the effect of
helmet use in a population of bicyclists who had experienced a crash.
We required that studies have complete outcome ascertainment, accurate
exposure measurement, appropriate selection of the comparison group
and elimination or control of factors such as selection bias,
observation bias and confounding.
DATA COLLECTION AND ANALYSIS: Five published studies met the selection
criteria. Two abstractors using a standard abstraction form
independently abstracted data. Odds ratios with 95% CI were calculated
for the protective effect of helmet for head and facial injuries.
Study results are presented individually. Head and brain injury
results were also summarized using meta-analysis techniques.
MAIN RESULTS: No randomized controlled trials were found. This review
identified five well conducted case control studies which met our
selection criteria. Helmets provide a 63%-88% reduction in the risk of
head, brain and severe brain injury for all ages of bicyclists.
Helmets provide equal levels of protection for crashes involving motor
vehicles (69%) and crashes from all other causes (68%). Injuries to
the upper and mid facial areas are reduced 65%. REVIEWER'S
CONCLUSIONS: Helmets reduce bicycle-related head and facial injuries
for bicyclists of all ages involved in all types of crashes including
those involving motor vehicles.
More details at :
http://mrw.interscience.wiley.com/cochrane/clsysrev/articles/CD001855/frame.html
bugbear
> Some reading if you are interested in cycle helmet research:
> http://www.ncbi.nlm.nih.gov/pubmed/10796827
Some reading if you are interested in cycle helmet research:
BugBear
Derek C
wrote:
Old Moore's Almanac might be better! I read one of the BHRF's hatchet
jobs on one of the pro-helmet studies, which showed a very significant
reduction in the percentage of serious head injuries for helmeted
riders (so no population effects) against non helmet wearers. The BHRF
argument was there was an almost insignificantly small possibility
(less than 5%) that the two results were not significantly different,
and in any case the helmets may may changed the behaviour of their
wearers, so that they where more likely to have an accident in the
first place.
Derek C
Derek C
wrote:
Old Moore's Almanac might be better!
I read one of the BHRF's hatchet jobs on one of the pro-helmet
studies, which showed a very significant reduction in the percentage
of serious head injuries for helmeted riders (so no population
effects) against non helmet wearers. The BHRF argument was there was
an almost insignificantly small possibility (less than 5%) that the
two results were not significantly different, and in any case the
helmets may have changed the behaviour of their wearers, so that they
JMS
I've looked at that site - it appears to have been put together by a
bunch of school-children.
Did you know that it was originally set up with the message:
"Helmets are not beneficial to cyclists - unless the evidence forces
them to a dramatically different conclusion."
When you look at the site, you can see it really is very, very biased
: and still trying to push that same message.
Many thanks for the suggestion.
--
Many cyclists are proving the need for registration by their contempt for the Highway Code and laws.
The answer:
All cyclists over 16 to take compulsory test, have compulsory insurance, and be registered.
Registration number to be clearly visible on the back of mandatory hi-viz vest.
Habitual law breakers' cycles confiscated and crushed.
(With thanks to KeithT for the idea)
JNugent
Thanks for the link.
The site has a FAQ page. Here are the (limited number of) questions posed
there, rhetorically or otherwise:
QUOTE: "How likely is head injury when cycling?"
OK, that's relevant - just.
QUOTE: "Are all head injuries a matter for concern?"
Is that relevant? The fact that the proprietors of the site don't regard head
injuries as worth protecting against cannot possibly be something that
researchers should take account of, can it?
QUOTE: "What evidence supports helmet use?"
Good, relevant question.
QUOTE: "What evidence is there that cycle helmets save lives?"
Relevant-ish, but put together in a weasel-ish way. Non-fatal head injuries
are worth protecting agaisnt, but the question is posed as they couldn't
possibly be. A nasty way to go about diverting attention from the issues.
QUOTE: "What evidence is there that cycle helmets reduce serious injury?"
Similar to the previous one, though not as bad, since this one does at least
suggest that serious head injuries (and not only fatal head injuries) might
be worth guarding against.
"QUOTE: Do helmet promotion and helmet laws affect cycle use?"
What is the relevance of that? None whatsoever.
QUOTE: "Is cycling without a helmet dangerous?"
Superficially relevant, though it could be subsumed under the (missing)
question "Does the wearing of head protection help prevent head injuries?".
I wonder why that - highly relevant - question is not in the FAQs? It must be
asked frequently.
QUOTE: "What is the balance of advantage?"
Doesn't sound all that relevant, does it?
QUOTE: "What is the cost-benefit of helmet use?"
OK-ish.
QUOTE: "What is the most effective way to make cycling safer?"
Totally irrelevant. It's analagous to "Why do I have to have good tread on my
car tyres and brakes kept properly maintained when road safety is already
addressed by breathalyser legislation?".
QUOTE: "If car occupants must wear seat belts, why shouldn't cyclists wear
helmets?"
Totally irrelevant.
JNugent
...as though that were a bad thing!
PhilO
>
> SELECTION CRITERIA: Controlled studies that evaluated the effect of
> helmet use in a population of bicyclists who had experienced a crash.
> We required that studies have complete outcome ascertainment, accurate
> exposure measurement, appropriate selection of the comparison group
> and elimination or control of factors such as selection bias,
> observation bias and confounding.
>
Hmm, as most of the papers they included were written by themselves,
it's
not really a surprise that they found out what they admit is "inherent
sense"
bugbear
> On Thu, 27 May 2010 12:10:56 +0100, bugbear
> <bugbear@trim_papermule.co.uk_trim> wrote:
>
>> JMS wrote:
>>> Some reading if you are interested in cycle helmet research:
>>> http://www.ncbi.nlm.nih.gov/pubmed/10796827
>> Some reading if you are interested in cycle helmet research:
>> www.cyclehelmets.org
>>
>> BugBear
>
>
> I've looked at that site - it appears to have been put together by a
> bunch of school-children.
Do you have a decent reference for this opinion - a peer
reviewed paper for example?
I'm afraid I can't just take your opinions
for things, even if they were to be well reasoned.
BugBear
Toom Tabard
And another of the myriad of wonderful statements on the same site,
where they've reviewed a paper which found helmets effective -
Title:-The effects of bicycling helmets in preventing significant
bicycle-related injuries in children
Conclusion:-The risk of serious head injury was significantly greater
when a helmet was not worn.
Criticism:-'It is not clear if helmets protect against non-serious
injuries.'
Toom
Toom Tabard
> Some reading if you are interested in cycle helmet research:http://www.ncbi.nlm.nih.gov/pubmed/10796827
>
>
> identified five well conducted case control studies which met our
> selection criteria. Helmets provide a 63%-88% reduction in the risk of
> head, brain and severe brain injury for all ages of bicyclists.
> Helmets provide equal levels of protection for crashes involving motor
> vehicles (69%) and crashes from all other causes (68%). Injuries to
> the upper and mid facial areas are reduced 65%. REVIEWER'S
>
> CONCLUSIONS: Helmets reduce bicycle-related head and facial injuries
> for bicyclists of all ages involved in all types of crashes including
> those involving motor vehicles.
>
I note their statements of equal levels of protection for crashes
involving motor vehicles, and on effect of helmets in mitigating
severe brain trauma.
That is as expected, and runs counter to the diet of inexpert claims
we hear on cycling newsgroups that they only work for slight injury
and simple spills, and do not work in accidents with other vehicles.
Fatal cycling accidents usually result from severe collision with
other vehicles, and there is also some interesting information and
data in the Transport Research Laboratory's recent report PPR438
'Analysis of police collision files for pedal cycling fatalities in
London,2001 - 2006',
The wider TRL report PPR 446 'The potential for cycle helmets to
prevent injury - a review of the evidence' is also interesting. (The
same, plus additional fatality data is discussed in Appendix H and
lists the effect of helmets making a significant difference in
severity of head trauma being the main cause of fatality).
Both reports are downloadable by registering (free) on TRL website
http://www.trl.co.uk/online_store/
They support the other reasonable evidence that helmets are effective,
can give advantages in all types of accidents and can mitigate
(sometimes crucially) the level of trauma throughout the whole
spectrum of mild to severe.
Toom
Mike Clark
Toom Tabard <to...@tabard.freeserve.co.uk> wrote:
>
> I note their statements of equal levels of protection for crashes
> involving motor vehicles, and on effect of helmets in mitigating
> severe brain trauma.
I also note included amongst the following are :-
References to studies included in this review
Thompson 1989 Thompson 1990 Thompson 1996 Thompson 1996a
References to studies excluded from this review
Spaite 1991
Spaite DW, Murphy M, Criss EA, Valenzuela TD, Meislin HW. A
prospective analysis of injury severity among helmeted and nonhelmeted
bicyclists involved in collisions with motor vehicles. Journal of Trauma
1991;31(11):1510-6.
Which had some interesting findings that initially goes along quite well
with Thompson's reported observations above.
Abstract: To evaluate the impact of helmet use on injury severity,
patient information was prospectively obtained for all bicyclists
involved in collisions with motor vehicles seen at a level-I trauma
center from January 1986 to January 1989. Two hundred ninety-eight
patients were evaluated; in 284 (95.3%, study group) cases there was
documentation of helmet use or nonuse. One hundred sixteen patients
(40.9%) wore helmets and 168 (59.1%) did not. One hundred ninety-nine
patients (70.1%) had an ISS <15, while 85 (29.9%) were severely
injured (ISS >15). Only 5.2% of helmet users (6/116) had an ISS >15
compared with 47.0% (79/168) of nonusers (p < 0.0001). The mean ISS
for helmet users was 3.8 compared with 18.0 for nonusers (p < 0.0001).
Mortality was higher for nonusers (10/168, 6.0%) than for helmet users
(1/116, 0.9%; p < 0.025).
But then Spaite et al decided to look closer at the non-head injuries
sustained by the cyclists and they found something that is also present
in the data from some of the studies of Thompson (but not commented on
by them).
A striking finding was noted when the group of patients without major
head injuries (246) was analyzed separately. Helmet users in this
group still had a much lower mean ISS (3.6 vs. 12.9, p < 0.001) and
were much less likely to have an ISS >15 (4.4% vs. 32.1%, p < 0.0001)
than were nonusers. In this group, 42 of 47 patients with an ISS >15
(89.4%) were not wearing helmets. We conclude that helmet nonuse is
strongly associated with severe injuries in this study population.
This is true even when the patients without major head injuries are
analyzed as a group; a finding to our knowledge not previously
described. This implies that nonusers of helmets tend to be in higher
impact crashes than helmet users, since the injuries suffered in body
areas other than the head also tend to be much more severe. It is
possible that at least some of the ''protection'' afforded helmet
wearers in previous studies may be explained by safer riding habits
rather than solely a direct effect of the helmets themselves.
It has also been shown in other published studies that the behaviour of
non-helmeted cyclists is significantly different from helmeted cyclists
e.g. they are also less likely to have hi-viz clothing, less likely to
have lit front and back lights, and less likely to comply with traffic
regulations.
Unfortunately these additional confounding factors are not tested for in
most of the studies reporting a protective factor for helmets against
head injuries (especially the papers by Thompson et al).
Mike
--
o/ \\ // |\ ,_ o Mike Clark
<\__,\\ // __o | \ / /\, "A mountain climbing, cycling, skiing,
"> || _`\<,_ |__\ \> | caving, antibody engineer and
` || (_)/ (_) | \corn computer user" http://www.antibody.me.uk/
Toom Tabard
> In message <3015d162-cd5f-4b63-8bb9-ee079f6ce...@o4g2000vbo.googlegroups.com>
JMS
wrote:
>In message <3015d162-cd5f-4b63...@o4g2000vbo.googlegroups.com>
> Toom Tabard <to...@tabard.freeserve.co.uk> wrote:
>
>>
>> I note their statements of equal levels of protection for crashes
>> involving motor vehicles, and on effect of helmets in mitigating
>> severe brain trauma.
>
>
>I also note included amongst the following are :-
>
>References to studies included in this review
>
>Thompson 1989 Thompson 1990 Thompson 1996 Thompson 1996a
>
>
>References to studies excluded from this review
>
>Spaite 1991
>
>Spaite DW, Murphy M, Criss EA, Valenzuela TD, Meislin HW. A
>prospective analysis of injury severity among helmeted and nonhelmeted
>bicyclists involved in collisions with motor vehicles. Journal of Trauma
>1991;31(11):1510-6.
There will be any number of papers *not* included.
You seem not to understand how such reviews work:
Criteria are set - and then searches and reviews are carried out.
Those papers which satisfy the search or review criteria are included;
those that don't are excluded.
You do not just include a paper because you *think* that it *ought*
to be included.
As the authors of the paper comment :
Some bicycling advocates have argued that helmeted cyclists may change
their riding behavior influenced by a greater feeling of security and,
thus take more risks and be more likely to crash (Hillman 1993). The
converse argument has also been made that helmeted cyclists may ride
more carefully and that these behaviors account for the reduction in
head injury, not helmet use (Spaite 1991). We believe these arguments
to be specious. The fundamental issue is whether or not when bicycle
riders crash and hit their heads they are benefited by wearing a
helmet. Cyclists would have to increase their risk taking four-fold to
overcome the protective effect of helmets. This seems unlikely. There
are no objective data to support this risk homeostasis theory, and
now, five case-control studies have demonstrated the protective effect
of helmets.
Toom Tabard
> In message <3015d162-cd5f-4b63-8bb9-ee079f6ce...@o4g2000vbo.googlegroups.com>
That abstract does not say, as you claim, that they 'looked closer at
the non-head injuries'. It says they looked at the group 'without
major head injuries'
If you score for head and rest of the body separately (the latter
would be non-head injuries) that tells more. If look at those without
major head injury, there is the problem of accommodation for helmet
wearers who might only be in that group because they were wearing
helmets. If you look at those who only had head injuries, there is the
question of helmet wearers who might not be there because they were
wearing helmets,etc.
And how is that relevant to helmets giving 'equal levels of protection
for crashes involving motor vehicles' - the same as e.g simple cycle
accidents with no other vehicle? The cyclist has less control of the
circumstances and force of impact where other vehicles are involved
(i.e any safer riding habits are diluted) but the protection is the
same.
And if 'at least some of the protection' is due to rider habits, that
would not affect the situation of a helmet per se having a further
substantial mitigating effect on such injuries as are sustained.
Toom
Derek C
The psycholists claim that cycle helmets do not significantly reduce
fatal and severe head injuries in the cycling population as a whole,
that helmets offer little protection in high speed impacts, and that
wearing helmets can change the behaviour of both cyclists and drivers,
for the better or for the worse.
There has been a significant reduction in cyclist KSI figures over the
period in which cycle helmet wearing has become more commonplace. Some
protection is usually better than non. Does the fact that the more
safety concious cyclists tend to wear helmets outweigh risk
compensation by others?
IMHO, the only way to find out if cycle helmets are effective is to
look at hospital studies, because this is when the things have
actually been tested in real life accidents. Perhaps the studies
should include the circumstances of the accident, the severity of the
injury and the outcome, e.g death, permanent diasablement, or complete
recovery.
Derek C
Peter Clinch
> There has been a significant reduction in cyclist KSI figures over the
> period in which cycle helmet wearing has become more commonplace.
And has been pointed out to you numerous times, correlation and
causation aren't necessarily bedmates. The KSI figures for
pedestrians has gone down at about the same rate as for cyclists
over the same period.
> Does the fact that the more
> safety concious cyclists tend to wear helmets outweigh risk
> compensation by others?
That's a good question. The data we have doesn't really allow us
to get a robust answer.
> IMHO, the only way to find out if cycle helmets are effective is to
> look at hospital studies, because this is when the things have
> actually been tested in real life accidents.
Population studies show what has actually happened to /everyone/
cycling. All the helmets tested in real life accidents will have
been worn by members of the whole population, so if they get to
pretty much any hospital then they'll be in the population data set
where they can influence the figures accordingly (and of course if
they're /not/ in there having not gone to hospital because of their
helmet then they'll register with a reduction in the rates of
cyclists presenting with serious head injuries, though it seems
that doesn't actually happen).
If the hospital studies you like so much were worth much for giving
a solid answer they'd come up with reproducible numbers, but AFAICT
from having looked at plenty they don't. One thing about the
population studies is they at least manage to come up with the same
general answer (that is, ca. zero effect with (potentially large)
error bars).
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 p.j.c...@dundee.ac.uk http://www.dundee.ac.uk/~pjclinch/
Derek C
wear helmets may be less seriously injured, or even uninjured, in a
given accident, so they will be less likely to be admitted to hospital
in the first place. So if anything, hospital studies will give an
under-estimate of the effectiveness of cycle helmets in preventing
deaths and serious injuries.
Derek C
JNugent
That had occurred to me too, on reading the preceding post.
Toom Tabard
> Derek C wrote:
> > There has been a significant reduction in cyclist KSI figures over the
> > period in which cycle helmet wearing has become more commonplace.
>
> And has been pointed out to you numerous times, correlation and
> causation aren't necessarily bedmates. The KSI figures for
> pedestrians has gone down at about the same rate as for cyclists
> over the same period.
>
Indeed, it is the fall in the number of cyclist KSI figures which has
resulted in cyclists displaying an increasing desire to wear helmets
as a fashion accessory.
Also of interest and great use is the discovery of the correlation
between increasing temperature and increased rate of chirping of
crickets. That means that you just need to make a few local crickets
chirp faster and you'll make it into a nice warm day. Global climate
scientists are now at work on methods to control the chirping rate of
crickets.
Toom
Peter Clinch
> I have also pointed out on a number of occasions that cyclists who
> wear helmets may be less seriously injured, or even uninjured, in a
> given accident, so they will be less likely to be admitted to hospital
> in the first place.
And if that happens then the rate of KSIs in the population will
drop, but that doesn't obviously happen beyond the rate of drop in
cycling overall, or the drop in KSI figures of groups with nothing
to with cycle helmets.
> So if anything, hospital studies will give an
> under-estimate of the effectiveness of cycle helmets in preventing
> deaths and serious injuries.
Population studies include the effects of people /not/ showing up.
And that effect appears to be about zero.
Toom Tabard
A good summary of the recent TRL report PPR 446 'The potential for
cycle helmets to prevent injury - a review of the evidence' is
http://www.dft.gov.uk/pgr/roadsafety/research/rsrr/theme1/ppr446.pdf
Including:-
Main Findings
Assuming that cycle helmets are a good fit and worn correctly, they
should be effective at reducing the
risk of head injury, in particular cranium fracture, scalp injury and
intracranial (brain) injury.
• Cycle helmets would be expected to be effective in a range of
accident conditions, particularly:
• the most common accidents that do not involve a collision with
another vehicle, often simple
falls or tumbles over the handlebars; and also
• when the mechanism of injury involves another vehicle glancing the
cyclist or tipping them over
causing their head to strike the ground.
• A specialist biomechanical assessment of over 100 police forensic
cyclist fatality reports predicted
that between 10 and 16% could have been prevented if they had worn an
appropriate cycle helmet.
• Of the on-road serious cyclist casualties admitted to hospital in
England (HES database):
• 10% suffered injuries of a type and to a part of the head that a
cycle helmet may have mitigated
or prevented; and a further
• 20% suffered ‘open wounds to the head’, some of which are likely to
have been to a part of the
head that a cycle helmet may have mitigated or prevented.
• Cycle helmets would be expected to be particularly effective for
children, because:
• the European Standard (EN 1078) impact tests and requirements are
the same for adult and
child cycle helmets – both use a 1.5 m drop height test; and so
• given that younger children are shorter than older children and
adults, their head height would
be within the drop height used in impact tests, so a greater
proportion of single-vehicle
accidents are likely to be covered by the Standard for children.
• No evidence was found for an increased risk of rotational head
injury with a helmet compared to
without a helmet.
The full report is downloadable by registering (free) on TRL
websitehttp://www.trl.co.uk/online_store/
Toom
Toom Tabard
> Derek C wrote:
> > I have also pointed out on a number of occasions that cyclists who
> > wear helmets may be less seriously injured, or even uninjured, in a
> > given accident, so they will be less likely to be admitted to hospital
> > in the first place.
>
> And if that happens then the rate of KSIs in the population will
> drop, but that doesn't obviously happen beyond the rate of drop in
> cycling overall, or the drop in KSI figures of groups with nothing
> to with cycle helmets.
>
> > So if anything, hospital studies will give an
> > under-estimate of the effectiveness of cycle helmets in preventing
> > deaths and serious injuries.
>
> Population studies include the effects of people /not/ showing up.
Not per se. That is meaningless unless and until you specify what
statistical population is being defined and studied and how it is
being studied.
> And that effect appears to be about zero.
A meaningless statement out of any context of study methodology.
Toom
JMS
<p.j.c...@dundee.ac.uk> wrote:
>Derek C wrote:
>
>> There has been a significant reduction in cyclist KSI figures over the
>> period in which cycle helmet wearing has become more commonplace.
You can of course back this up with figures
>If the hospital studies you like so much were worth much for giving
>a solid answer they'd come up with reproducible numbers, but AFAICT
>from having looked at plenty they don't. One thing about the
>population studies is they at least manage to come up with the same
>general answer (that is, ca. zero effect with (potentially large)
>error bars).
>
>Pete.
OK show us some serious research which show that cycle helmets have
had no - or a "detrimental" effect on head injuries.
JMS
How dare you publicise such information !!!!
Tony Raven
> A good summary of the recent TRL report PPR 446 'The potential for
> cycle helmets to prevent injury - a review of the evidence' is
> available at
>
> http://www.dft.gov.uk/pgr/roadsafety/research/rsrr/theme1/ppr446.pdf
>
>
You clearly haven't read the report itself or my summary of its failings
posted earlier. Their predictions of lives saved are based on their
assumption that helmets are 50% effective
But since they say "Overall, it is concluded that it is not possible to
determine definitively from the literature the level of effectiveness of
cycle helmets", that would appear to be a dodgy assumption.
--
Tony
" I would never die for my beliefs because I might be wrong."
Bertrand Russell
Derek C
> Toom Tabard wrote:
> > A good summary of the recent TRL report PPR 446 'The potential for
> > cycle helmets to prevent injury - a review of the evidence' is
> > available at
>
> >http://www.dft.gov.uk/pgr/roadsafety/research/rsrr/theme1/ppr446.pdf
>
> You clearly haven't read the report itself or my summary of its failings
> posted earlier. Their predictions of lives saved are based on their
> assumption that helmets are 50% effective
>
> But since they say "Overall, it is concluded that it is not possible to
> determine definitively from the literature the level of effectiveness of
> cycle helmets", that would appear to be a dodgy assumption.
>
> --
> Tony
>
and nowhere does it make that specific claim. It twice mentions a
range of 10-50% effectiveness, and other than that reports the figures
in the various study papers, with much more balanced comments than are
found in 'cyclehelmets.org'.
Derek C
Tony Raven
> On May 29, 11:11 pm, Tony Raven <tra...@gotadsl.co.uk> wrote:
>> You clearly haven't read the report itself or my summary of its failings
>> posted earlier. Their predictions of lives saved are based on their
>> assumption that helmets are 50% effective
>>
>> But since they say "Overall, it is concluded that it is not possible to
>> determine definitively from the literature the level of effectiveness of
>> cycle helmets", that would appear to be a dodgy assumption.
>>
>>
> I have TRL PPR446 downloaded on my computer. I have read through it
> and nowhere does it make that specific claim. It twice mentions a
> range of 10-50% effectiveness, and other than that reports the figures
> in the various study papers, with much more balanced comments than are
> found in 'cyclehelmets.org'.
>
> Derek C
Chapter 6: The Extent and Nature of Cyclist Head Injuries: The Real
World Potential Effectiveness of Cycle Helmets
Document page 36, pdf page 46, last paragraph continuing over to next page:
"The effectiveness of cycle helmets in single-vehicle collisions was
estimated to be 50%. <....> The effectiveness of a cycle helmet in
collisions with a car was assumed to be lower than that for impacts with
the ground. In the absence of any definitive estimates, a range of 10 to
30% is used for the following assessment. <....> However, it should be
remembered that there was no specific evidence to support these
estimates. The estimated potential fatal casualty savings are shown in
Table 6-7."
Chapter 5: A Literature Review of Cycle Helmet Effectiveness
Document page 27, PDF page 37, third paragraph from the bottom and
bottom paragraph:
"Overall, it is concluded that it is not possible to determine
definitively from the literature the level of effectiveness of cycle
helmets as none of the reviewed studies controlled fully for all
possible confounding variables and it is likely that this would be
difficult to achieve. <....>
This is not to say that cycle helmets are or are not effective in
reducing the risk of head injuries; rather that limitations in the data
available mean that it would be very difficult for such studies to
control for all possible confounding factors, and it would therefore be
difficult to make a definitive claim for cycle helmet effectiveness."
Curiously though they then go on to make definitive claims for their
effectiveness in Chapter 6.
Your apology will be graciously accepted.
Derek C
effectiveness for cycle helmets in various types of accident,rather
than one definitive figure of 50%. This is far more reasonable than
'cyclehelmets.org' which always assumes an effectiveness of zero!
Derek C
Toom Tabard
> Toom Tabard wrote:
> > A good summary of the recent TRL report PPR 446 'The potential for
> > cycle helmets to prevent injury - a review of the evidence' is
> > available at
>
> >http://www.dft.gov.uk/pgr/roadsafety/research/rsrr/theme1/ppr446.pdf
>
> You clearly haven't read the report itself or my summary of its failings
> posted earlier. Their predictions of lives saved are based on their
> assumption that helmets are 50% effective
>
> But since they say "Overall, it is concluded that it is not possible to
> determine definitively from the literature the level of effectiveness of
> cycle helmets", that would appear to be a dodgy assumption.
>
Yes, I've read the report, They are suitably cautious in their claims
and conclusions. Same with their other report on fatal accidents,
where they say specifically they've verged on the side of caution
regarding their estimate of percentage of lives that could be saved.
I'm merely drawing attention to their report for those who might find
it of interest, but generally it supports what I've also concluded
from a variety of other sources.
Toom
Toom Tabard
They are saying from the literature studies that it is not possible to
determine definitively the effectiveness, because of the limiting
factors of such studies.
They are saying from some real world accident data it is possible to
conclude effectiveness in single vehicle accidents with simple impact
with the ground, but they can only make cautious estimate of
effectivenes in collisions with cars.
Where is the information is not there in one source, but specific
information is available form another source, what is wrong with
reaching reaching conclusions from the information that is actually
there. Their conclusions of helmets being 'particularly' effective in
single vehicle accidents is reasonably derived from this. But there
again, I another one who you say 'clearly haven't read the report
itself'. ;-)
Toom
Toom Tabard
> > A good summary of the recent TRL report PPR 446 'The potential for
> > cycle helmets to prevent injury - a review of the evidence' is
> > available at
>
> >http://www.dft.gov.uk/pgr/roadsafety/research/rsrr/theme1/ppr446.pdf
>
> You clearly haven't read the report itself or my summary of its failings
> posted earlier. Their predictions of lives saved are based on their
> assumption that helmets are 50% effective
>
> But since they say "Overall, it is concluded that it is not possible to
> determine definitively from the literature the level of effectiveness of
> cycle helmets", that would appear to be a dodgy assumption.
>
That is a somewhat selective misrepresentation of what is in the
report.
They are saying effectiveness cannot be derived from the information
in the literature.
In their own study where detailed information on injuries and
circumstances are available, they are deriving 50% effectiveness in
one category involving 15% of cases, 10-30% effectiveness in one other
category involving 27% of cases, and 0% effectiveness in other
catergories involving 58% of cases. And they make it clear they are
only talking of mitigation from fatal to most likely serious head
injury.
Toom
JMS
<p.j.c...@dundee.ac.uk> wrote:
>Derek C wrote:
>
>> There has been a significant reduction in cyclist KSI figures over the
>> period in which cycle helmet wearing has become more commonplace.
>
>And has been pointed out to you numerous times, correlation and
>causation aren't necessarily bedmates. The KSI figures for
>pedestrians has gone down at about the same rate as for cyclists
>over the same period.
I wonder why it is you tell these outright lies?
Do you assume that people do not have access to the figures?
Or - perhaps you think that they trust your word.
Well - you are wrong - however you look at the comparison of
pedestrian and cycling accident figures over say the last 6 years.
Look at the number of pedestrians and cyclists killed or seriously
injured in 2008 and compare those figures with the previous years.
Pedestrian figures for 2008 are lower than every year since and
including 2002 - a massive 24% reduction on the 2002 figures. (There
is only one year when they were not lower then the previous year)
Look at the cycling figures : the 2008 figure is actually *higher*
than 3 of the preceding years - and for three years the figure went up
or remained the same as previous year.
If you compare the 2008 KSI cycling figure with 2002 then you will see
a reduction of only 2.5%
So - pedestrian reduction over 6 years : 24%
and cyclist reduction over the same period 2.5%
You are a blatant liar.
(figures per billion passenger kilometres)
Peter Clinch
> So you admit that TRL PPR446 suggests a range of possible
> effectiveness for cycle helmets in various types of accident,rather
> than one definitive figure of 50%. This is far more reasonable than
> 'cyclehelmets.org' which always assumes an effectiveness of zero!
Cyclehelmets.org doesn't make any such /assumption/, it makes
findings from available data.
Yet again you mis-characterise people who don't come to the same
conclusion as you.
Derek C
> Derek C wrote:
> > So you admit that TRL PPR446 suggests a range of possible
> > effectiveness for cycle helmets in various types of accident,rather
> > than one definitive figure of 50%. This is far more reasonable than
> > 'cyclehelmets.org' which always assumes an effectiveness of zero!
>
> Cyclehelmets.org doesn't make any such /assumption/, it makes
> findings from available data.
>
> Yet again you mis-characterise people who don't come to the same
> conclusion as you.
>
> Pete.
> --
useless for preventing serious head injuries, that equates to zero
effectiveness as far as I am concerned. Not that I believe that, and
neither do the TRL!
Derek C
Tony Raven
>
> That is a somewhat selective misrepresentation of what is in the
> report.
>
> They are saying effectiveness cannot be derived from the information
> in the literature.
>
> In their own study where detailed information on injuries and
> circumstances are available, they are deriving 50% effectiveness in
> one category involving 15% of cases, 10-30% effectiveness in one other
> category involving 27% of cases, and 0% effectiveness in other
> catergories involving 58% of cases. And they make it clear they are
> only talking of mitigation from fatal to most likely serious head
> injury.
>
They are not deriving at all - show me where in the report you claim
they derive it.
The 50%, the 10-30% figure is a total guess by them with no evidential
basis and they say as much at several places in the report.
Tony Raven
No they say it is an estimate (but don't show how they estimated it)
that they assumed.
>
> Where is the information is not there in one source, but specific
> information is available form another source, what is wrong with
> reaching reaching conclusions from the information that is actually
> there.
But there is no evidence for their 50% figure and they say so
themselves. Its a guess.
Their conclusions of helmets being 'particularly' effective in
> single vehicle accidents is reasonably derived from this. But there
> again, I another one who you say 'clearly haven't read the report
> itself'. ;-)
Their conclusion is if you assume helmets are effective then you should
prevent some deaths. But there is no more reason to assume they are
effective than to assume they are not effective and in the latter case
you won't save any deaths.
If you have read the report then please quote me the page locations
where they derive the 50% effectiveness figure. And someone clearly
hasn't read the report if they claim things aren't in the report when
they very clearly are.
Roland Perry
Sun, 30 May 2010, JMS <jmsmi...@live.co.uk> remarked:
>Look at the cycling figures : the 2008 figure is actually *higher*
>than 3 of the preceding years - and for three years the figure went up
>or remained the same as previous year.
Is that figure a "per UK", or "per km" or something else?
The reason I ask is because there has been a big increase (people say)
in cycling as a result of "carbon footprint" issues. And this increase
is quite likely biassed towards commuting in busy urban areas - with
relatively inexperienced cyclists who perhaps bring some of their
car-driving habits with them - except they forget they don't have a
padded tin can round them any more.
--
Roland Perry
Peter Clinch
> On May 30, 6:47 pm, Peter Clinch <p.j.cli...@dundee.ac.uk> wrote:
>> Derek C wrote:
>>> So you admit that TRL PPR446 suggests a range of possible
>>> effectiveness for cycle helmets in various types of accident,rather
>>> than one definitive figure of 50%. This is far more reasonable than
>>> 'cyclehelmets.org' which always assumes an effectiveness of zero!
>> Cyclehelmets.org doesn't make any such /assumption/, it makes
>> findings from available data.
>>
>> Yet again you mis-characterise people who don't come to the same
>> conclusion as you.
> Since both you and 'cyclehelmets.org' claim that cycle helmets are
> useless for preventing serious head injuries
First up, neither of us are claiming that. That you can't understand
what's actually being said is your problem.
> that equates to zero
> effectiveness as far as I am concerned. Not that I believe that, and
> neither do the TRL!
What you've missed is the difference between an assumption and a
conclusion. An assumption is an unproven start point, *not* a
conclusion. If you look at your data and come to a conclusion, that is
not an assumption. If you start with an assumption and process your
data using that assumption is a /very/ different thing.
Derek C
> In message <if7506l0sot8seeu9bfpbekm8uj13gi...@4ax.com>, at 18:23:55 on
> Sun, 30 May 2010, JMS <jmsmith2...@live.co.uk> remarked:
>
> >Look at the cycling figures : the 2008 figure is actually *higher*
> >than 3 of the preceding years - and for three years the figure went up
> >or remained the same as previous year.
>
> Is that figure a "per UK", or "per km" or something else?
>
> The reason I ask is because there has been a big increase (people say)
> in cycling as a result of "carbon footprint" issues. And this increase
> is quite likely biassed towards commuting in busy urban areas - with
> relatively inexperienced cyclists who perhaps bring some of their
> car-driving habits with them - except they forget they don't have a
> padded tin can round them any more.
> --
The following article from the Guardian discusses this issue:
http://www.guardian.co.uk/uk/2009/nov/05/cycling-deaths-department-of-transport
A large number of relatively inexperienced, or out of practice,
cyclists taking to the roads on bikes because of the economic downturn
and the ever increasing cost of motoring and public transport may the
main reasons for the increased number of cycling casualties.
Derek C
> Sun, 30 May 2010, JMS <jmsmith2...@live.co.uk> remarked:
>
> >Look at the cycling figures : the 2008 figure is actually *higher*
> >than 3 of the preceding years - and for three years the figure went up
> >or remained the same as previous year.
>
> Is that figure a "per UK", or "per km" or something else?
>
> The reason I ask is because there has been a big increase (people say)
> in cycling as a result of "carbon footprint" issues. And this increase
> is quite likely biassed towards commuting in busy urban areas - with
> relatively inexperienced cyclists who perhaps bring some of their
> car-driving habits with them - except they forget they don't have a
> padded tin can round them any more.
> --
> Roland Perry
The following article from the Guardian discusses this issue:
http://www.guardian.co.uk/uk/2009/nov/05/cycling-deaths-department-of-transport
A large number of relatively inexperienced, or out of practice,
cyclists taking to the roads on bikes because of the economic downturn
and the ever increasing cost of motoring and public transport may be
the main reasons for the increased number of cycling casualties.
Derek C
Derek C
assumption that cycle helmets are ineffective for preventing fatal and
serious head injuries and then tries to prove this by dodgy use of
statistics. The TRL report draws conclusions after looking at the
available data.
Derek C
Peter Clinch
> As far as I can see, 'cyclehelmets.org' always starts with the
> assumption that cycle helmets are ineffective for preventing fatal and
> serious head injuries and then tries to prove this by dodgy use of
> statistics. The TRL report draws conclusions after looking at the
> available data.
You have that entirely the wrong way around. Answer Tony's questions
about where the effectiveness is derived in the TRL piece.
BHRF suggests there's no tangible effect at the population level having
looked at what's happened to serious head injuries in the wake of
increasing helmet use.
Mr. Benn
news:86fml6...@mid.individual.net...
> Derek C wrote:
>
>> So you admit that TRL PPR446 suggests a range of possible
>> effectiveness for cycle helmets in various types of accident,rather
>> than one definitive figure of 50%. This is far more reasonable than
>> 'cyclehelmets.org' which always assumes an effectiveness of zero!
>
> Cyclehelmets.org doesn't make any such /assumption/, it makes findings
> from available data.
Correction: Carefully selected available data.
Peter Clinch
Any statistical study that didn't make careful selection of its data a
priority would come up with daft results. For an excellent example, see
TRT '89...
When it comes to BHRF, they're not actually doing the original research
but rather looking through the available research. And doing that they
(and I) found out that the studies coming to a conclusion of around no
effectiveness have the most sensible data sets for the job. And despite
using different populations the results seem to be reproducible, not the
case with small scale case/control studies.
Just zis Guy, you know?
> there is no evidence for their 50% figure and they say so
> themselves. Its a guess.
It's also beyond the scope of their brief, which was to summarise
existing research not to come up with novel (and inexplicable)
syntheses. As I understand it they were seduced by the "biomechanical
evidence" of one individual and wanted to give it greater prominence
than could be justified by its presence in the published research, but
it could just as easily be simple cluelessness.
--
Guy
Derek C
> Derek C wrote:
> > As far as I can see, 'cyclehelmets.org' always starts with the
> > assumption that cycle helmets are ineffective for preventing fatal and
> > serious head injuries and then tries to prove this by dodgy use of
> > statistics. The TRL report draws conclusions after looking at the
> > available data.
>
> You have that entirely the wrong way around. Answer Tony's questions
> about where the effectiveness is derived in the TRL piece.
> BHRF suggests there's no tangible effect at the population level having
> looked at what's happened to serious head injuries in the wake of
> increasing helmet use.
>
AFAICS, helmets do make a signficant difference (reduction) to the
severity of head injuries suffered by cyclists who do bang their heads
in the course of an accident, even if they represent only a relatively
small percentage of the total cycling population. Are you claiming
that wearing helmets is not beneficial to these individuals?
Derek C
Peter Clinch
> AFAICS, helmets do make a signficant difference (reduction) to the
> severity of head injuries suffered by cyclists who do bang their heads
> in the course of an accident, even if they represent only a relatively
> small percentage of the total cycling population. Are you claiming
> that wearing helmets is not beneficial to these individuals?
AFAICS your basis for that is assumption rather than analysis of a large
data set.
REgardless of that, I'm not claiming that a helmet cannot be a benefit
to an individual. And nor, AFAICT, is BHRF.
If you weren't so brash in your assumptions of who says what you
wouldn't keep hanging yourself out to dry with unsupportable accusations
and pronouncements.
Derek C
> Derek C wrote:
> > AFAICS, helmets do make a signficant difference (reduction) to the
> > severity of head injuries suffered by cyclists who do bang their heads
> > in the course of an accident, even if they represent only a relatively
> > small percentage of the total cycling population. Are you claiming
> > that wearing helmets is not beneficial to these individuals?
>
> AFAICS your basis for that is assumption rather than analysis of a large
> data set.
>
> to an individual. And nor, AFAICT, is BHRF.
>
difference at a population level?
Derek C
Peter Clinch
One doesn't follow from the other. Either way around.
I make the claim because that is what the figures appear to show at the
population level.
What that means is that you can't predict a certain positive safety
benefit (at the "serious" level) from wearing a helmet for a notional
cyclist setting out on a notional trip. The specific details of their
trip may mean they're they might be better off, they might be worse off,
it might be irrelevant, but there isn't actually a way with current data
to say which it will be, just that the combined effects across all
notional cyclists on notional trips come out to around zero.
That's not the same thing at all as saying in an actual accident with
particular circumstances our notional cyclist /may/ be better off with a
helmet on.
They're genuinely quite different states of affairs and do not
contradict one another.
JMS
wrote:
Have a guess at what : (figures per billion passenger kilometres)
means
Mike Clark
Toom Tabard <to...@tabard.freeserve.co.uk> wrote:
> On 29 May, 12:36, Peter Clinch <p.j.cli...@dundee.ac.uk> wrote:
> > Derek C wrote:
> > > There has been a significant reduction in cyclist KSI figures over the
> > > period in which cycle helmet wearing has become more commonplace.
And from the DfT figures there has been a significant reduction in
pedestrian KSI figures over the period in which cycle helmet wearing (by
cyclists) has become more commonplace.
The numbers are what the numbers are, they don't prove cause and effect
they just tell us that things seem to be changing.
> >
> > And has been pointed out to you numerous times, correlation and
> > causation aren't necessarily bedmates. �The KSI figures for
> > pedestrians has gone down at about the same rate as for cyclists
> > over the same period.
> >
>
> Indeed, it is the fall in the number of cyclist KSI figures which has
> resulted in cyclists displaying an increasing desire to wear helmets
> as a fashion accessory.
>
> Also of interest and great use is the discovery of the correlation
> between increasing temperature and increased rate of chirping of
> crickets. That means that you just need to make a few local crickets
> chirp faster and you'll make it into a nice warm day. Global climate
> scientists are now at work on methods to control the chirping rate of
> crickets.
>
> Toom
We've been here before in this thread with the actual figures as
published by the DfT
In message <c3215e0b51....@mrc7acorn1.path.cam.ac.uk> I said
Correlation is not proof of causation.
Take a look for example at the DfT figures in
In particular look at Figure 7.1b on page 104 in section 7.
You will see quite clearly that there has been a general trend in the
reduction of fatality rates for both pedestrians and cyclists over a
similar timescale. If anything the trend for a reduction of pedestrian
fatalities is greater than for cyclists.
So pedestrian fatalities have also reduced during a period when you
claim that cyclehelmet wearing (by cyclists!) has become much more
commonplace. However it doesn't seem plausible to believe that
cyclehelmet wearing is the cause of this reduction in fatalities of
pedestrians even if there is a correlation with time and the wearing of
cyclehelmets by cyclists.
Perhaps there is some other explanation?
Another reasonable hypothesis is that improvements in car design, and
also perhaps changes in driving behaviour, have resulted in reduced
severity of accidents involving both pedestrians and cyclists when in
collision with a motor vehicle.
Mike
--
o/ \\ // |\ ,_ o Mike Clark
<\__,\\ // __o | \ / /\, "A mountain climbing, cycling, skiing,
"> || _`\<,_ |__\ \> | caving, antibody engineer and
` || (_)/ (_) | \corn computer user"
Mike Clark
Derek C <del.co...@tiscali.co.uk> wrote:
Those who choose to wear a cycle helmet under conditions of
non-compulsion clearly have other associated factors. They have been
shown to more likely comply with road traffic regulations, they have
been shown to more likely wear hi viz clothing and have lit front and
back lights on their cycles at night.
They have also been shown to have fewer serious injuries of all types.
However as has repeatedly been said statistical association is not proof
of causation.
Now is it wearing the helmet that causes the lights to be lit?
Is wearing the helmet that causes the cyclists to obey road traffic
regulations?
So does it necessarily follow from just the statistics that wearing the
helmet causes a reduction in all types of injury (not just head
injuries).
JMS
wrote:
<snip>
>Take a look for example at the DfT figures in
>
>http://tinyurl.com/yyodye9
>
>In particular look at Figure 7.1b on page 104 in section 7.
>
>You will see quite clearly that there has been a general trend in the
>reduction of fatality rates for both pedestrians and cyclists over a
>similar timescale. If anything the trend for a reduction of pedestrian
>fatalities is greater than for cyclists.
And if you look at the stats for KSI you will see that the figures for
pedestrians shows a much greater reduction than for cyclists. Indeed
there are 3 years out of the previous 6 (from memory) where the KSI
rate for cyclists has gone up.
So yes - a like for like reduction in fatalities as medical expertise
has improved - but an increase in KSI for cyclists and not for
pedestrians.
Cycling is certainly a more dangerous means of transport than walking
- and is getting worse year on year.
--
2008 DfT Figures: Passenger casualty rates Per billion passenger kilometers:
Killed or seriously injured: Pedal Cyclists : 541 Pedestrians 382
All casualties: Pedal Cyclists : 3814 Pedestrians : 1666
(Pedal cyclist casualties up 9% - pedestrians up 2%: Cycling is becoming more dangerous each year when compared to walking as a means of transport)
Roland Perry
Mon, 31 May 2010, JMS <jmsmi...@live.co.uk> remarked:
>>>Look at the cycling figures : the 2008 figure is actually *higher*
>>>than 3 of the preceding years - and for three years the figure went up
>>>or remained the same as previous year.
>>
>>Is that figure a "per UK", or "per km" or something else?
>>
>>The reason I ask is because there has been a big increase (people say)
>>in cycling as a result of "carbon footprint" issues. And this increase
>>is quite likely biassed towards commuting in busy urban areas - with
>>relatively inexperienced cyclists who perhaps bring some of their
>>car-driving habits with them - except they forget they don't have a
>>padded tin can round them any more.
>
>Have a guess at what : (figures per billion passenger kilometres)
>means
I didn't see that in your posting. Sorry. So the figures are consistent
with the proposition that there are lots of new inexperienced cyclists
having a really bad time, who are depressing the average.
--
Roland Perry
Derek C
> In message <3e7336bc-df20-4195-a963-3aaea1466...@o15g2000vbb.googlegroups.com>
The general reduction in cyclist KSI could be due to a greater
incidence of helmet wearing, although the average psycholist would
have to be dragged over hot coals before they would admit it!
pk
news:C44BFqJf...@perry.co.uk...
>
> I didn't see that in your posting. Sorry. So the figures are consistent
> with the proposition that there are lots of new inexperienced cyclists
> having a really bad time, who are depressing the average.
> --
> Roland Perry
so the advise oft given here "Cycle instead of walking - it is safer" is
plain wrong when used to encourage people new to cycling?
pk
Mike Clark
Derek C <del.co...@tiscali.co.uk> wrote:
Quoting the DfT
In particular look at Figure 7.1b on page 104 in section 7.
"Source: Department for Transport. In 2008, the reported fatality
rate for pedestrians was 60 per cent lower than the 1980 level and for
pedal cyclists it was 59 per cent lower."
Clearly not only do cyclists wearing cycle helmets protect cyclists from
injuries they also protect pedestrians from injuries as well.
Mike
--
o/ \\ // |\ ,_ o Mike Clark
<\__,\\ // __o | \ / /\, "A mountain climbing, cycling, skiing,
"> || _`\<,_ |__\ \> | caving, antibody engineer and
` || (_)/ (_) | \corn computer user" http;//www.antibody.me.uk/
Peter Clinch
> The general reduction in cyclist KSI could be due to a greater
> incidence of helmet wearing, although the average psycholist would
> have to be dragged over hot coals before they would admit it!
FSVO "psycholist".
I have no trouble admitting it /could/ be, though the evidence
suggests far too many confounding factors to make it even as good
as odds-on, and certainly not good enough to say it's a no-brainer
to wear one because they're definitely a big safety win (and by
extension, that anyone disagreeing with such a position is a kook
with blood on their hands).
You, OTOH, would appear to need dragging over something quite a bit
hotter than hot coals to admit the general reduction is KSI might
not be down to helmets.
DavidR
> And if you look at the stats for KSI you will see that the figures for
> pedestrians shows a much greater reduction than for cyclists. Indeed
> there are 3 years out of the previous 6 (from memory) where the KSI
> rate for cyclists has gone up.
>
> Cycling is certainly a more dangerous means of transport than walking
> - and is getting worse year on year.
Curious. Someone's being trying to tell me that helmets and hi-viz are some
kind of safety gear. Have wearing rates declined over the period in
question? Maybe my eyes deceive me.
Derek C
> "JMS" <jmsmith2...@live.co.uk > wrote
More people have started to cycle to work in the last couple of years,
due to the economic downturn. The slight increase in cyclist KSI
during this period is mainly down to this. That at least destroys the
critical mass argument! See:
http://www.guardian.co.uk/news/datablog/2009/nov/06/cycle-casualties-deaths-statistics
Ingo Keck
> On May 31, 11:07 pm, "DavidR" <cured...@4bidden.org.uk> wrote:
> > "JMS" <jmsmith2...@live.co.uk > wrote
[...]
> > > Cycling is certainly a more dangerous means of transport than walking
> > > - and is getting worse year on year.
> >
> > Curious. Someone's being trying to tell me that helmets and hi-viz are some
> > kind of safety gear. Have wearing rates declined over the period in
> > question? Maybe my eyes deceive me.
>
> More people have started to cycle to work in the last couple of years,
> due to the economic downturn. The slight increase in cyclist KSI
> during this period is mainly down to this. That at least destroys the
> critical mass argument! See:
>
> http://www.guardian.co.uk/news/datablog/2009/nov/06/
> cycle-casualties-deaths-statistics
Then it may be the effect of the helmet. Not really unexpected if you
think of Rodgers et al who found in 1988 that cyclist deaths are
positivly correlated with increased helmet ownership in the USA and of
course also all the studies related to helmet laws that evaluated the
change in injury risk for the cyclists.
The "critical mass argument"? Are you referring to "safety in numbers?"
This argument not only applies to cyclists, it is also known since
decades to apply to cars as a student of traffic engineering has told
me... People tend to forget this just to put the fault on the cyclist.
Does someone have a link to the helmet wearing rates in the UK the last
years? Or an article reference?
Ingo.
Tony Raven
>
> Does someone have a link to the helmet wearing rates in the UK the last
> years? Or an article reference?
>
http://www.dft.gov.uk/pgr/roadsafety/research/rsrr/theme1/PPR420.pdf
--
Tony
" I would never die for my beliefs because I might be wrong."
Bertrand Russell
Tony Raven
> Ingo Keck wrote:
>
>>
>> Does someone have a link to the helmet wearing rates in the UK the last
>> years? Or an article reference?
>>
>
> http://www.dft.gov.uk/pgr/roadsafety/research/rsrr/theme1/PPR420.pdf
>
P.S. The data above provides a bit of a problem for Derek. Child
cyclist K and KSI rates have been declining faster than for adult
cyclists yet as the graph shows child helmet wearing rates haven't
changed while those of adults have doubled since 1994.
Perhaps its the helmets that're slowing the decline in adult cyclist
deaths and serious injuries ;-)
Mike Clark
Derek C <del.co...@tiscali.co.uk> wrote:
Could you point me to the published research that you have
relied on for your statement, and which contains the p values that
indicate that the statistical analysis of data pertaining to a
hypothesis on safety in numbers is tested and has been invalidated?
Mike
--
o/ \\ // |\ ,_ o Mike Clark
<\__,\\ // __o | \ / /\, "A mountain climbing, cycling, skiing,
"> || _`\<,_ |__\ \> | caving, antibody engineer and
` || (_)/ (_) | \corn computer user" http://www.antibody.me.uk/
Derek C
> Tony Raven wrote:
> > Ingo Keck wrote:
>
> >> Does someone have a link to the helmet wearing rates in the UK the last
> >> years? Or an article reference?
>
> >http://www.dft.gov.uk/pgr/roadsafety/research/rsrr/theme1/PPR420.pdf
>
> P.S. The data above provides a bit of a problem for Derek. Child
> cyclist K and KSI rates have been declining faster than for adult
> cyclists yet as the graph shows child helmet wearing rates haven't
> changed while those of adults have doubled since 1994.
>
> Perhaps its the helmets that're slowing the decline in adult cyclist
> deaths and serious injuries ;-)
>
> --
days. Anyone can buy a bike from Halfords and take it straight on the
road with no training or proficiency testing whatsover. When I was at
school back in the 1950s, it was expected that you were trained and
tested on the school playground before you where allowed to cycle on
the public highway. Helmets are only a secondary precaution in case
someone else does something silly.
Derek C
Derek C
> > Ingo Keck wrote:
>
> >> Does someone have a link to the helmet wearing rates in the UK the last
> >> years? Or an article reference?
>
> >http://www.dft.gov.uk/pgr/roadsafety/research/rsrr/theme1/PPR420.pdf
>
> P.S. The data above provides a bit of a problem for Derek. Child
> cyclist K and KSI rates have been declining faster than for adult
> cyclists yet as the graph shows child helmet wearing rates haven't
> changed while those of adults have doubled since 1994.
>
> Perhaps its the helmets that're slowing the decline in adult cyclist
> deaths and serious injuries ;-)
>
I think the big problem is the lack of cycle training these days.
Derek C
> In message <36c46196-fe2c-4c84-a411-ff464ff18...@a20g2000vbc.googlegroups.com>
> Derek C <del.copel...@tiscali.co.uk> wrote:
>
>
>
>
>
> > On May 31, 11:07 pm, "DavidR" <cured...@4bidden.org.uk> wrote:
> > > "JMS" <jmsmith2...@live.co.uk > wrote
>
> > > > And if you look at the stats for KSI you will see that the figures for
> > > > pedestrians shows a much greater reduction than for cyclists. Indeed
> > > > there are 3 years out of the previous 6 (from memory) where the KSI
> > > > rate for cyclists has gone up.
>
> > > > Cycling is certainly a more dangerous means of transport than walking
> > > > - and is getting worse year on year.
>
> > > Curious. Someone's being trying to tell me that helmets and hi-viz
> > > are some kind of safety gear. Have wearing rates declined over the
> > > period in question? Maybe my eyes deceive me.
>
> > More people have started to cycle to work in the last couple of years,
> > due to the economic downturn. The slight increase in cyclist KSI
> > during this period is mainly down to this. That at least destroys the
> > critical mass argument! See:
>
>
> Could you point me to the published research that you have
> relied on for your statement, and which contains the p values that
> indicate that the statistical analysis of data pertaining to a
> hypothesis on safety in numbers is tested and has been invalidated?
>
> Mike
> --
that it hasn't been invalidated! I would imagine this hypothesis is
hard to prove either way. Holland has relative low cyclist KSI rate
because it has wide boulevards and often separate cycle tracks, not
because large number of people cycle.
Derek C
Tony Raven
>
> Could you point me to the published research that you have relied on
> for your statement, and which contains the p values that indicate
> that the statistical analysis of data pertaining to a hypothesis on
> safety in numbers is tested and has been invalidated?
>
Reference to Jacobsen's work and why this data has greater validity
would be helpful too
Derek C
> Quoting the DfT
>
> http://tinyurl.com/yyodye9
>
> In particular look at Figure 7.1b on page 104 in section 7.
>
> "Source: Department for Transport. In 2008, the reported fatality
> rate for pedestrians was 60 per cent lower than the 1980 level and for
> pedal cyclists it was 59 per cent lower."
>
> Clearly not only do cyclists wearing cycle helmets protect cyclists from
> injuries they also protect pedestrians from injuries as well.
>
the patients at a home for epileptics in my area, who are prone to
sudden collapse or banging their heads very hard on the ground during
epileptic fits. Apparently the helmets are very effective in
preventing serious head injuries.
Derek C
Tony Raven
>
> Only if you can point me at validated statistical research that shows
> that it hasn't been invalidated! I would imagine this hypothesis is
> hard to prove either way. Holland has relative low cyclist KSI rate
> because it has wide boulevards and often separate cycle tracks, not
> because large number of people cycle.
>
http://injuryprevention.bmj.com/content/9/3/205.full and references therein.
Your turn!
Mike Clark
Derek C <del.co...@tiscali.co.uk> wrote:
> On Jun 1, 9:42�am, Mike Clark <mrc7-...@cam.ac.uk> wrote:
> > In message <36c46196-fe2c-4c84-a411-ff464ff18...@a20g2000vbc.googlegroups.com>
> > � � � � � Derek C <del.copel...@tiscali.co.uk> wrote:
[snip]
> >
> > > More people have started to cycle to work in the last couple of years,
> > > due to the economic downturn. The slight increase in cyclist KSI
> > > during this period is mainly down to this. That at least destroys the
> > > critical mass argument! �See:
> >
> > >http://www.guardian.co.uk/news/datablog/2009/nov/06/cycle-casualties-...
> >
> > Could you point me to the published research that you have
> > relied on for your statement, and which contains the p values that
> > indicate that the statistical analysis of data pertaining to a
> > hypothesis on safety in numbers is tested and has been invalidated?
> Only if you can point me at validated statistical research that shows
> that it hasn't been invalidated! I would imagine this hypothesis is
> hard to prove either way. Holland has relative low cyclist KSI rate
> because it has wide boulevards and often separate cycle tracks, not
> because large number of people cycle.
>
> Derek C
I didn't make the statement "That at least destroys the critical mass
argument!" and then give as a source to the essential test as a Guardian
newspaper blog, so I think it's you whose made the statement and needs
to provide your source of evidence.
Peter Clinch
> I know of a group of pedestrians who do wear cycle helmets. They are
> the patients at a home for epileptics in my area, who are prone to
> sudden collapse or banging their heads very hard on the ground during
> epileptic fits. Apparently the helmets are very effective in
> preventing serious head injuries.
It's a group with a particularly high risk of a head injury of the sort
that an EN1078 helmet will be good for.
A bit like MTBing under lots of low overhanging branches, for example,
for which job I'd personally be happy to wear a helmet.
But on the roads doing A to B I'm not at a particularly high risk of
that sort of accident, so why does it make particular sense to wear such
a device for that specific job?
Mike Clark
Derek C <del.co...@tiscali.co.uk> wrote:
And the relevance of that personal observation in comparison to a DfT
report that pedestrian fatalities have reduced by 60% between 1980 and
2008 is?
Peter Clinch
> I think the big problem is the lack of cycle training these days.
> Anyone can buy a bike from Halfords and take it straight on the road
> with no training or proficiency testing whatsover. When I was at
> school back in the 1950s, it was expected that you were trained and
> tested on the school playground before you where allowed to cycle on
> the public highway.
These days available cycle training is rather better than faffing about
with cones in the school playground. Aside from anything else, you get
to go on real roads and deal with real situations.
And who are the main driving forces behind this? Oh, it's that bunch of
"psycholists" at the CTC, who are doing something very directly
addressing what you see as "the big problem" at the same time as you're
writing them off as kooks with blood on their hands.
At the primary school my kids are at P7 have had cycle lessons spread
over a whole term, more and better than the Cycling Proficiency that was
available in my day. And it's increasingly common, thanks in very large
part to CTC.
(btw, I'm a cycle trainer accredited with Cycling Scotland despite
shamelessly cycling around without a helmet on).
Tony Raven
>
> I know of a group of pedestrians who do wear cycle helmets. They are
> the patients at a home for epileptics in my area, who are prone to
> sudden collapse or banging their heads very hard on the ground during
> epileptic fits. Apparently the helmets are very effective in
> preventing serious head injuries.
>
But apparently that anecdotal effect doesn't work for pedestrians in
general.
Tatsuhiro Y et al, The Effectiveness of Wearing Pedestrian Helmets while
Walking from Home to School in Elementary School Children, Third
International Conference on Injury Control and Prevention, Melbourne,
Australia, February 1996
(A study of 89,000 school children over 5 years, 33,000 of whom wore
helmets and 56,000 didn't for the duration of the study.
Conclusions: There was no significant difference between children
wearing helmets and those not wearing helmets in the incidence of all
injuries and head injuries by Xy test.)
Perhaps you'll have better luck with finding evidence for these helmets
http://www.zoomergear.com/product.html
Derek C
> Derek C wrote:
> > I know of a group of pedestrians who do wear cycle helmets. They are
> > the patients at a home for epileptics in my area, who are prone to
> > sudden collapse or banging their heads very hard on the ground during
> > epileptic fits. Apparently the helmets are very effective in
> > preventing serious head injuries.
>
> It's a group with a particularly high risk of a head injury of the sort
> that an EN1078 helmet will be good for.
>
> A bit like MTBing under lots of low overhanging branches, for example,
> for which job I'd personally be happy to wear a helmet.
>
> But on the roads doing A to B I'm not at a particularly high risk of
> that sort of accident, so why does it make particular sense to wear such
> a device for that specific job?
>
> Pete.
Because, like the epileptics, I might bump my head very hard against a
hard surface or a vehicle, should I be unfortunate enough to have an
accident on my bike. Sort of common sense really, an attribute usually
lacking in academics in my experience!
Derek C
Derek C
> Derek C wrote:
> > I think the big problem is the lack of cycle training these days.
> > Anyone can buy a bike from Halfords and take it straight on the road
> > with no training or proficiency testing whatsover. When I was at
> > school back in the 1950s, it was expected that you were trained and
> > tested on the school playground before you where allowed to cycle on
> > the public highway.
>
> These days available cycle training is rather better than faffing about
> with cones in the school playground. Aside from anything else, you get
> to go on real roads and deal with real situations.
>
> And who are the main driving forces behind this? Oh, it's that bunch of
> "psycholists" at the CTC, who are doing something very directly
> addressing what you see as "the big problem" at the same time as you're
> writing them off as kooks with blood on their hands.
>
> At the primary school my kids are at P7 have had cycle lessons spread
> over a whole term, more and better than the Cycling Proficiency that was
> available in my day. And it's increasingly common, thanks in very large
> part to CTC.
>
> (btw, I'm a cycle trainer accredited with Cycling Scotland despite
> shamelessly cycling around without a helmet on).
>
So had all those extra, allegedly new and inexperienced, cyclists who
were killed or seriously injured in the second quarter of 2009 taken
cycling lessons? I rather suspect not.
Derek C
Patrick Gosling
Derek C <del.co...@tiscali.co.uk> wrote:
>Because, like the epileptics, I might bump my head very hard against a
>hard surface or a vehicle, should I be unfortunate enough to have an
>accident on my bike. Sort of common sense really, an attribute usually
>lacking in academics in my experience!
When was the last time you climbed a ladder?
-patrick.
Derek C
> In article <bd68880b-77f8-458f-86d2-356c4ca1f...@a20g2000vbc.googlegroups.com>,
> Derek C <del.copel...@tiscali.co.uk> wrote:
>
> >Because, like the epileptics, I might bump my head very hard against a
> >hard surface or a vehicle, should I be unfortunate enough to have an
> >accident on my bike. Sort of common sense really, an attribute usually
> >lacking in academics in my experience!
>
> When was the last time you climbed a ladder?
>
> -patrick.
Never on a bicycle!
Derek
Peter Clinch
> Because, like the epileptics, I might bump my head very hard against a
> hard surface or a vehicle, should I be unfortunate enough to have an
> accident on my bike.
You might bump it very hard against the pavement, just like they do. So
you /do/ wear one to walk to the shops in case of a trip and fall, yes?
> Sort of common sense really, an attribute usually
> lacking in academics in my experience!
You're the one parading your academic credentials time and time again,
not me!
Mike Clark
Derek C <del.co...@tiscali.co.uk> wrote:
If all that was necessary was "common sense" there would be no need for
academics to conduct detailed research and analyse the results. (It's
after all common sense that the world is flat and stationery and that
the sun moves past overhead.)
Besides which the types of helmets recommended for epileptics are not
bicycle helmets because they don't offer the right types of protection.
see for example
http://www.epilepsy.com/articles/ar_1064604624
"Not all types of helmets offer adequate protection. Bicycle helmets
are comfortable and good-looking, but they do not offer the best
protection for injuries from seizure activity. Coverage is
insufficient in the back and on the sides of the head. When seizures
cause forward falls, they do not protect the face, and if they are not
adjusted properly, they move too much. Longevity of the helmet is
another problem. With repeated hard falls, a bicycle helmet may
crack."
Derek C
> Derek C wrote:
> > Because, like the epileptics, I might bump my head very hard against a
> > hard surface or a vehicle, should I be unfortunate enough to have an
> > accident on my bike.
>
> You might bump it very hard against the pavement, just like they do. So
> you /do/ wear one to walk to the shops in case of a trip and fall, yes?
>
> > Sort of common sense really, an attribute usually
> > lacking in academics in my experience!
>
> You're the one parading your academic credentials time and time again,
> not me!
At least I earned my living in the real world after graduating.
Derek
Peter Clinch
> So had all those extra, allegedly new and inexperienced, cyclists who
> were killed or seriously injured in the second quarter of 2009 taken
> cycling lessons? I rather suspect not.
I suspect not too, the upswing in training won't have caught them.
But it is worth noting that while you've been making such a fuss about
something you've now admitted is secondary to safety, the CTC (who
you've been remarkably rude about) have actually been doing genuinely
useful work on what you have said is the big issue.
Mike Clark
Derek C <del.co...@tiscali.co.uk> wrote:
What's the real world in your definition?
Mike
--
o/ \\ // |\ ,_ o Mike Clark
<\__,\\ // __o | \ / /\, "A mountain climbing, cycling, skiing,
"> || _`\<,_ |__\ \> | caving, antibody engineer and
` || (_)/ (_) | \corn computer user" http://www.antibody.me.uk/
Derek C
> In message <bd68880b-77f8-458f-86d2-356c4ca1f...@a20g2000vbc.googlegroups.com>
the purpose, but look like rounded cycle helmets or skateboard
helmets. I would personally be happier with cycle helmets if they
covered more of your head and did not have pseudo aerodynamic shapes.
I have removed the plastic peak on my current one, because it slightly
restricted my vision, and I was worried about it catching on
something.
As a general question, would people be happier to wear them if they
were stronger and more like lightweight and ventilated motorcycle
helmets?
Derek
Patrick Gosling
When you're up to answering the question as posed, could you also
indicate whether you wore a safety helmet, and if not, why not?
-patrick.
Derek C
> In article <2a472ed4-5f39-4330-9c5a-fc5cd4b4b...@l6g2000vbo.googlegroups.com>,
> Derek C <del.copel...@tiscali.co.uk> wrote:
>
> >On Jun 1, 11:25 am, j...@eng.cam.ac.uk (Patrick Gosling) wrote:
> >> In article
> ><bd68880b-77f8-458f-86d2-356c4ca1f...@a20g2000vbc.googlegroups.com>,
> >> Derek C <del.copel...@tiscali.co.uk> wrote:
>
> >> >Because, like the epileptics, I might bump my head very hard against a
> >> >hard surface or a vehicle, should I be unfortunate enough to have an
> >> >accident on my bike. Sort of common sense really, an attribute usually
> >> >lacking in academics in my experience!
>
> >> When was the last time you climbed a ladder?
>
> >> -patrick.
>
> >Never on a bicycle!
>
> When you're up to answering the question as posed, could you also
> indicate whether you wore a safety helmet, and if not, why not?
>
to wear a hard hat and a safety harness. The bottom of the ladder had
to be secured. 'Ealth 'n Safety requirements mate.
Derek
Patrick Gosling
And when you climb a ladder at home?
[ this is like squeezing blood from a stone, but perhaps we'll get there
eventually ]
-patrick.
Derek C
> In message <a612097e-1cbb-48bf-9ff5-511757829...@y12g2000vbg.googlegroups.com>
> Derek C <del.copel...@tiscali.co.uk> wrote:
>
>
>
>
>
> > On Jun 1, 11:41 am, Peter Clinch <p.j.cli...@dundee.ac.uk> wrote:
> > > Derek C wrote:
> > > > Because, like the epileptics, I might bump my head very hard
> > > > against a hard surface or a vehicle, should I be unfortunate
> > > > enough to have an accident on my bike.
>
> > > You might bump it very hard against the pavement, just like they do.
> > > So you /do/ wear one to walk to the shops in case of a trip and
> > > fall, yes?
>
> > > > Sort of common sense really, an attribute usually
> > > > lacking in academics in my experience!
>
> > > You're the one parading your academic credentials time and time
> > > again, not me!
>
> > At least I earned my living in the real world after graduating.
>
> > Derek
>
> What's the real world in your definition?
>
> Mike
Anything private sector, although I admit I did work as a Scientific
Civil Servant for a few years.
Derek
Mike Clark
Derek C <del.co...@tiscali.co.uk> wrote:
So they're not like the cycle helmets in common use then?
> I would personally be happier with cycle helmets if they covered more
> of your head and did not have pseudo aerodynamic shapes. I have
> removed the plastic peak on my current one, because it slightly
> restricted my vision, and I was worried about it catching on
> something.
>
> As a general question, would people be happier to wear them if they
> were stronger and more like lightweight and ventilated motorcycle
> helmets?
>
> Derek
Why the emphasis on strength? My understanding is that much of the
serious brain damage is caused by the brain sloshing around inside the
skull as a result of deceleration and tortional forces.
Mike
--
o/ \\ // |\ ,_ o Mike Clark
<\__,\\ // __o | \ / /\, "A mountain climbing, cycling, skiing,
"> || _`\<,_ |__\ \> | caving, antibody engineer and
` || (_)/ (_) | \corn computer user" http://www.antibody.me.uk/
Mike Clark
Derek C <del.co...@tiscali.co.uk> wrote:
Well on those grounds I know lots of academics who also earn a living in
the real world e.g. in commercially sponsored research, consultancy,
technology licensing, company spinouts, corporate directorships etc etc
Derek C
> In message <3292c818-e709-4944-bb2e-9905b2e5a...@e28g2000vbd.googlegroups.com>
Motorcycle and motor racing helmets are considerably stronger and
stiffer than cycle helmets, but people seem to survive very high g
crashes in them, even if they are concussed for a while. You have a
much greater chance of surviving an accident if your skull is not
smashed to pieces. In any case cycle helmets reduce the g loading on
the brain by at least a factor of 4, as well as reducing the
probability of skull fractures.
Derek
Tom Crispin
wrote:
>In article <99f2a2f7-7d37-4719...@y21g2000vba.googlegroups.com>,
>Derek C <del.co...@tiscali.co.uk> wrote:
>>On Jun 1, 12:11�pm, j...@eng.cam.ac.uk (Patrick Gosling) wrote:
>>> In article <2a472ed4-5f39-4330-9c5a-fc5cd4b4b...@l6g2000vbo.googlegroups.com>,
>>> Derek C �<del.copel...@tiscali.co.uk> wrote:
>>>
>>> >On Jun 1, 11:25�am, j...@eng.cam.ac.uk (Patrick Gosling) wrote:
>>> >> In article
>>> ><bd68880b-77f8-458f-86d2-356c4ca1f...@a20g2000vbc.googlegroups.com>,
>>> >> Derek C �<del.copel...@tiscali.co.uk> wrote:
>>>
>>> >> >Because, like the epileptics, I might bump my head very hard against a
>>> >> >hard surface or a vehicle, should I be unfortunate enough to have an
>>> >> >accident on my bike. Sort of common sense really, an attribute usually
>>> >> >lacking in academics in my experience!
>>>
>>> >> When was the last time you climbed a ladder?
>>>
>>> >> -patrick.
>>>
>>> >Never on a bicycle!
>>>
>>> When you're up to answering the question as posed, could you also
>>> indicate whether you wore a safety helmet, and if not, why not?
>>>
>>On the rare occasions I had to climb a ladder at work, I was required
>>to wear a hard hat and a safety harness. The bottom of the ladder had
>>to be secured. 'Ealth 'n Safety requirements mate.
>
>And when you climb a ladder at home?
I do not know what you are trying to get at.
I cycle almost daily without a cycle helmet, and my step ladder at
home comes out a most twice a year. I don't wear a helmet on those
occasions either.
Due to the frequency of my cycling I expect that wearing a correctly
fitted cycle helmet when cycling would be far more likely to protect
me from a serious head injury that wearing a correctly fitted climbing
helmet when using a step ladder.
I wonder what percentage of ladder accidents involve injury to the
head anyway. Probably a far smaller percentage than head injuries
following a cycling accident.
Mike Clark
Tom Crispin <kije....@this.bit.freeuk.com.munge> wrote:
But that's the same logical argument that would also lead to the
conclusion that given the amount of time you spend walking up and down
stairs, or the number of occasions you take a shower, that you'd
generally be much better off wearing a helmet on those occasions!
>
> I wonder what percentage of ladder accidents involve injury to the
> head anyway. Probably a far smaller percentage than head injuries
> following a cycling accident.
Aren't you confusing the probability of having a serious accident in any
one single period of an activity with the overall probability of having
a serious accident from repeated exposure to the same activity?
If there is no reason to wear a helmet for any one selected exposure to
risk, what about two exposures, four exposures, eight exposures etc?
At what point do you decide there is a transition to a requirement to
wear a helmet to compensate for the risk? Also why is the risk greater
on the nth occasion than it was on the 1st?
Peter Clinch
> At least I earned my living in the real world after graduating.
So I take it that those of us working in the public sector that
disagree with you are useless wasters, while those that agree with
you (say, those responsible for the research you love to trumpet)
are excellent people working for august institutions and doing
first class work? What a convenient separation!
I guess the holes we've pointed out in that research don't amount
to anything as we fall into the former category, and thus must be
wrong...
Derek C
> Derek C wrote:
> > At least I earned my living in the real world after graduating.
>
> So I take it that those of us working in the public sector that
> disagree with you are useless wasters, while those that agree with
> you (say, those responsible for the research you love to trumpet)
> are excellent people working for august institutions and doing
> first class work? What a convenient separation!
>
> I guess the holes we've pointed out in that research don't amount
> to anything as we fall into the former category, and thus must be
> wrong...
>
> Pete.
Research is also done in the private sector you know.
Derek
Mike Clark
Derek C <del.co...@tiscali.co.uk> wrote:
Yes and it's very interesting to see what happens to such research when
it doesn't support the commercial aims of the organisation concerned.
The tobacco industry did a lot of research into the effects of smoking
and the mining industry did a lot of research into the effects of
inhalation of dust and exposure to various minerals and radioisotopes.
How much of that research was immediately put out into the public view?
What of the research that goes on in the pharmaceutical sector whereby
one company might compare their own drug with those of their rivals, or
their own expensive drug with a cheaper version?
Tom Crispin
wrote:
Rubbish.
I spend about 5 minutes a day in the shower, and 2 hours a day, on
average (based on ~8000 miles per year at ~10mph), cycling.
I would not even want to try to calculate the time I spend per day
climbing ladders, it probably amounts to seconds. Stairs too are
difficult to calculate, I live in a ground floor flat and there are
few steps at work, again it is probably seconds or low minutes.
Wearing a helmet for those 2 hours a day on average cycling would have
a far greater advantage to me than wearing a helmet while showering,
climbing ladders and walking up stairs combined.
>> I wonder what percentage of ladder accidents involve injury to the
>> head anyway. Probably a far smaller percentage than head injuries
>> following a cycling accident.
>
>Aren't you confusing the probability of having a serious accident in any
>one single period of an activity with the overall probability of having
>a serious accident from repeated exposure to the same activity?
No. I was wondering what percentage of ladder accidents involved head
injury compared with cycling accidents involved head injury, and
expecting that cycling accidents are far more likely to result in a
head injury.
>If there is no reason to wear a helmet for any one selected exposure to
>risk, what about two exposures, four exposures, eight exposures etc?
>At what point do you decide there is a transition to a requirement to
>wear a helmet to compensate for the risk? Also why is the risk greater
>on the nth occasion than it was on the 1st?
I was considering overall exposure.
And I never said that the risk is greater on the nth occasion than on
the first - but that is a false argument anyway. Although the risk on
the nth exposure is exactly the same as on the first exposure, the
risk of an event occurring sometime during n exposures is exactly n
times greater than the event occurring on the first exposure.
If you want your arguments against cycle helmet use to stand up to
scrutiny you could start by making sense of your arguments. And the
best argument against cycle helmet use is the example of the
Netherlands. The European country which has the lowest cyclist head
injury rates also has the lowest helmet use among cyclists of any
European country.
Trying to make the argument by suggesting that if people want to wear
a cycle helmet then they should also wear helmets while they wash
their hair does you no credit at all.
Derek C
> In message <c008c0c3-c7c1-4e9c-8fc6-4364e094e...@y12g2000vbg.googlegroups.com>
> Derek C <del.copel...@tiscali.co.uk> wrote:
>
>
>
>
>
> > On Jun 1, 5:05 pm, Peter Clinch <p.j.cli...@dundee.ac.uk> wrote:
> > > Derek C wrote:
> > > > At least I earned my living in the real world after graduating.
>
> > > So I take it that those of us working in the public sector that
> > > disagree with you are useless wasters, while those that agree with
> > > you (say, those responsible for the research you love to trumpet)
> > > are excellent people working for august institutions and doing
> > > first class work? What a convenient separation!
>
> > > I guess the holes we've pointed out in that research don't amount
> > > to anything as we fall into the former category, and thus must be
> > > wrong...
>
> > > Pete.
>
> > Research is also done in the private sector you know.
>
> > Derek
>
> Yes and it's very interesting to see what happens to such research when
> it doesn't support the commercial aims of the organisation concerned.
>
> The tobacco industry did a lot of research into the effects of smoking
> and the mining industry did a lot of research into the effects of
> inhalation of dust and exposure to various minerals and radioisotopes.
>
> How much of that research was immediately put out into the public view?
>
> What of the research that goes on in the pharmaceutical sector whereby
> one company might compare their own drug with those of their rivals, or
> their own expensive drug with a cheaper version?
>
products, and to find cheaper and more environmentally friendly ways
of producing them.
Derek