I despair, I really do.

in message <[email hidden]>, Peter Clinch

(') said:

Quoted message said:

So am I pro or anti helmets ? I'm certainly against comlpulsion, but I
don't see that helmets are overall a BAD thing in any specific way.

Bad in themselves, no.

If the rotation injury hypothesis were to be shown to be correct, then they
would undoubtedly be shown to be bad in themselves (although only
marginally because it's clear that the number of aggravated injuries can't
be large). But if the number of aggravated injuries is equal to or greater
than the number of ameliorated injuries (and by my reading of the data
that seems to be the case), then you have to say helmets are bad in
themselves.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

((DoctorWho)ChristopherEccleston).act();
uk.co.bbc.TypecastException: actor does not want to be typecast.
[adapted from autofile on /., 31/03/05]

Simon Brooke said:

in message <[email hidden]>, Peter Clinch

(') said:

Quoted message said:

So am I pro or anti helmets ? I'm certainly against comlpulsion, but I
don't see that helmets are overall a BAD thing in any specific way.

Bad in themselves, no.

If the rotation injury hypothesis were to be shown to be correct, then they
would undoubtedly be shown to be bad in themselves (although only
marginally because it's clear that the number of aggravated injuries can't
be large). But if the number of aggravated injuries is equal to or greater
than the number of ameliorated injuries (and by my reading of the data
that seems to be the case), then you have to say helmets are bad in
themselves.

Any minute now Ziggy will be along to argue that a helmet could *possibly*
save your life...as could cosmic rays or the fateful alignment of planets;
but he'll insist that (irrespecetive of the overall view) this is an vital
contribution.

_ said:

Any minute now Ziggy will be along to argue that a helmet could *possibly*
save your life...as could cosmic rays or the fateful alignment of planets;
but he'll insist that (irrespecetive of the overall view) this is an vital
contribution.

No he won't.

The target audience for persuasion already believe that.

What needs to be done is to convince them that the number of occasions
when that will happen is so absurdly small that, taking all the
disadvantages into consideration you are better off not wearing one.

Further to that, on the matter of compulsion, since there are many day
to day activities that offer a far greater chance of head injury than
cycling, it would be absurd to make helmet wearing compulsory when
cycling unless you had previously made it compulsory for walking down
the strret, going down stairs, and, for all I know, travelling in a car!

But if asked if it possible that a hemet will save you life, my answer
would be something along the lines of "Yes, there is a microscopically
small chance that a helmet could save your life.", because to me, that
is the honest answer.

Simon Brooke said:

If the rotation injury hypothesis were to be shown to be correct, then they
would undoubtedly be shown to be bad in themselves (although only
marginally because it's clear that the number of aggravated injuries can't
be large). But if the number of aggravated injuries is equal to or greater
than the number of ameliorated injuries (and by my reading of the data
that seems to be the case), then you have to say helmets are bad in
themselves.

I don't see why if the plusses *equal* the minuses... In that case
I'd say they're irrelevant. I suppose you could mark them down for
having a finite and unnecessary cost and degree of faff, but lots
of people spend money they don't need to on things that make their
life a little harder (fashion clothing being the obvious case in
point).

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

"Tony Raven" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

OG wrote on 28/04/2007 03:13 +0100:

<Snip>

Quoted message said:

So have a look at the evidence and do what every helmet
proponent I have challenged has so far failed to do and tell me at which
horizontal tick mark that step change occured.
http://cycling.raven-family.com/Helmet%20Graphs.jpg

Nice. Do you have figures for the amount of cycle use over the same period
for the countries?

Just Visiting wrote on 28/04/2007 19:12 +0100:

Quoted message said:

"Tony Raven" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

OG wrote on 28/04/2007 03:13 +0100:

<Snip>

Quoted message said:

So have a look at the evidence and do what every helmet
proponent I have challenged has so far failed to do and tell me at which
horizontal tick mark that step change occured.
http://cycling.raven-family.com/Helmet%20Graphs.jpg

Nice. Do you have figures for the amount of cycle use over the same period
for the countries?

Yes it dropped dramatically - between 20 and 60% IIRC correctly so with
so many fewer people cycling and all of them wearing helmets so gaining
an 85% reduction in head injuries it should be really really easy to
spot where the helmet law was introduced and a massive reduction in head
injuries resulted. Step up, step up!

--
Tony

"The most savage controversies are those about matters as to which there
is no good evidence either way."
- Bertrand Russell

Peter Clinch said:

Simon Brooke said:

If the rotation injury hypothesis were to be shown to be correct,
then they would undoubtedly be shown to be bad in themselves
(although only marginally because it's clear that the number of
aggravated injuries can't be large). But if the number of
aggravated injuries is equal to or greater than the number of
ameliorated injuries (and by my reading of the data that seems to
be the case), then you have to say helmets are bad in themselves.

I don't see why if the plusses *equal* the minuses... In that case
I'd say they're irrelevant. I suppose you could mark them down for
having a finite and unnecessary cost and degree of faff, but lots
of people spend money they don't need to on things that make their
life a little harder (fashion clothing being the obvious case in
point).

Except that, so far as I am aware, there is no law (current or in
prospect) mandating fashion clothing. If the safety effect is
irrelevant (equally balanced), then they are bad in themselves
precisely because they add unnecessary cost and aggravation to cycling
(in the opinion of many).

Of course, it might be that you're factoring that in - so the safety
benefit comes out slightly plus, but that's balanced by the extra cost
and whatnot, but that's not what Simon said - he said if the safety
balances (supposing that the sum of the effect of the aggravated
matches the sum of the effect of the ameliorated - I'm assuming that's
what he meant by "number of"😉, then helmets are bad. I agree.

regards, Ian SMith
--
|\ /| no .sig
|o o|
|/ \|

Ian Smith wrote on 28/04/2007 20:53 +0100:

Quoted message said:

Except that, so far as I am aware, there is no law (current or in
prospect) mandating fashion clothing. If the safety effect is
irrelevant (equally balanced), then they are bad in themselves
precisely because they add unnecessary cost and aggravation to cycling
(in the opinion of many).

Ah but consider the Zippy perspective. Spending money on fashion
clothing means you are less likely to be able to afford that sports car
so less likely to kill yourself driving too fast. So fashion clothing
could save your life. ;-)

--
Tony

"The most savage controversies are those about matters as to which there
is no good evidence either way."
- Bertrand Russell

Tony Raven said:

Yes it dropped dramatically - between 20 and 60% IIRC correctly so with
so many fewer people cycling and all of them wearing helmets so gaining
an 85% reduction in head injuries it should be really really easy to
spot where the helmet law was introduced and a massive reduction in head
injuries resulted. Step up, step up!

Unless helmet use rates increased fairly steadily up to and after the
introduction of a MHL.

Ian Smith said:

Except that, so far as I am aware, there is no law (current or in
prospect) mandating fashion clothing. If the safety effect is
irrelevant (equally balanced), then they are bad in themselves
precisely because they add unnecessary cost and aggravation to cycling
(in the opinion of many).

Though at present there is, thank the lord, no such law, but people
are willing to pay for the aggravation anyway. Particularly true
of roadies that want to look the part.

Quoted message said:

Of course, it might be that you're factoring that in - so the safety
benefit comes out slightly plus, but that's balanced by the extra cost
and whatnot

No. I'm being a bit reductionist and taking out the numpties
trying to force them on us if lots of the rest of us wear them, and
am going just on the physical "am I better off or not, right this
moment, about to have A Random Serious Accident, in a plastic hat".
On those grounds, if safety plusses equal safety negatives then
it's irrelevant whether I wear it or not unless I can predict what
sort of accident I might be in in advance (and of course I can't).

When you factor in the human side of it, in the current climate I'd
agree they're bad on balance. But if (Ha!) the human side of it
was sorted then I doubt it would matter whether or not folk wore
them as far as safety went

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

Tom Crispin wrote on 28/04/2007 21:17 +0100:

Quoted message said:

Tony Raven said:

Yes it dropped dramatically - between 20 and 60% IIRC correctly so with
so many fewer people cycling and all of them wearing helmets so gaining
an 85% reduction in head injuries it should be really really easy to
spot where the helmet law was introduced and a massive reduction in head
injuries resulted. Step up, step up!

Unless helmet use rates increased fairly steadily up to and after the
introduction of a MHL.

They increased over the year preceding the legislation and then doubled
to approx 100% when the legislation was introduced.

--
Tony

"The most savage controversies are those about matters as to which there
is no good evidence either way."
- Bertrand Russell

Tony Raven said:

Ian Smith wrote on 28/04/2007 20:53 +0100:

Quoted message said:

Except that, so far as I am aware, there is no law (current or in
prospect) mandating fashion clothing. If the safety effect is
irrelevant (equally balanced), then they are bad in themselves
precisely because they add unnecessary cost and aggravation to cycling
(in the opinion of many).

Ah but consider the Zippy perspective. Spending money on fashion
clothing means you are less likely to be able to afford that sports car
so less likely to kill yourself driving too fast. So fashion clothing
could save your life. ;-)

Yes, Tony but not every butterfly that flaps its wings in Beijing causes
a storm in Paris ;-)

Peter Clinch wrote on 28/04/2007 21:52 +0100:

Quoted message said:

When you factor in the human side of it, in the current climate I'd
agree they're bad on balance. But if (Ha!) the human side of it was
sorted then I doubt it would matter whether or not folk wore them as far
as safety went

Even if they were completely neutral on safety ground they would be bad
on balance because the impression they give that cycling is so uniquely
dangerous that it requires special protective equipment. Just the
impression you don't need to encourage more cycling.

--
Tony

"The most savage controversies are those about matters as to which there
is no good evidence either way."
- Bertrand Russell

Ian Smith said:

Except that, so far as I am aware, there is no law (current or in
prospect) mandating fashion clothing.

Tell that to Stephen Gough(!)

in message <[email hidden]>, Ian Smith

(') said:

Peter Clinch said:

Simon Brooke said:

If the rotation injury hypothesis were to be shown to be correct,
then they would undoubtedly be shown to be bad in themselves
(although only marginally because it's clear that the number of
aggravated injuries can't be large). But if the number of
aggravated injuries is equal to or greater than the number of
ameliorated injuries (and by my reading of the data that seems to
be the case), then you have to say helmets are bad in themselves.

I don't see why if the plusses *equal* the minuses... In that case
I'd say they're irrelevant. I suppose you could mark them down for
having a finite and unnecessary cost and degree of faff, but lots
of people spend money they don't need to on things that make their
life a little harder (fashion clothing being the obvious case in
point).

Except that, so far as I am aware, there is no law (current or in
prospect) mandating fashion clothing. If the safety effect is
irrelevant (equally balanced), then they are bad in themselves
precisely because they add unnecessary cost and aggravation to cycling
(in the opinion of many).

Of course, it might be that you're factoring that in - so the safety
benefit comes out slightly plus, but that's balanced by the extra cost
and whatnot, but that's not what Simon said - he said if the safety
balances (supposing that the sum of the effect of the aggravated
matches the sum of the effect of the ameliorated - I'm assuming that's
what he meant by "number of"😉, then helmets are bad. I agree.

Well, I was sloppy with my wording, but it's more complex than that.
Helmets do ameliorate minor injuries in low-speed impacts - they will save
you from minor bruising or minor laceration of the scalp. There's no
question about that. If the rotation injury hypothesis is true, the
injuries they aggravate are very serious ones - ones causing permanent
brain damage and death.

I don't see how you can come up with a calculus which says 'n minor bumps
and scratches is worth the same as m permanent brain damage'. All the
statistics show is that number of deaths and serious injuries doesn't
significantly change; the statistics don't show whether there's a
systematic reduction in the number of 'injuries' which would never have
made it to a hospital anyway. So I'm essentially leaving any systematic
reduction in scratches and bruises out of the equation, and just counting
deaths and serious injuries. If helmets cause (even very slightly) more
deaths than they save (which seems to be the case) then they're a bad
thing. If the number of deaths is not affected but helmets aggravate even
very slightly more permanent brain injuries than they ameliorate, then
they are a bad thing.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/
Das Internet is nicht fuer gefingerclicken und giffengrabben... Ist
nicht fuer gewerken bei das dumpkopfen. Das mausklicken sichtseeren
keepen das bandwit-spewin hans in das pockets muss; relaxen und
watchen das cursorblinken. -- quoted from the jargon file

Tony Raven said:

Peter Clinch wrote on 28/04/2007 21:52 +0100:

Quoted message said:

When you factor in the human side of it, in the current climate I'd
agree they're bad on balance. But if (Ha!) the human side of it was
sorted then I doubt it would matter whether or not folk wore them as
far as safety went

Even if they were completely neutral on safety ground they would be bad
on balance because the impression they give that cycling is so uniquely
dangerous that it requires special protective equipment. Just the
impression you don't need to encourage more cycling.

Though (a) that's the human side of it, and (b) note the "Ha!" in
the above.

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

Simon Brooke said:

Well, I was sloppy with my wording, but it's more complex than that.
Helmets do ameliorate minor injuries in low-speed impacts - they will save
you from minor bruising or minor laceration of the scalp. There's no
question about that. If the rotation injury hypothesis is true, the
injuries they aggravate are very serious ones - ones causing permanent
brain damage and death.

I don't see how you can come up with a calculus which says 'n minor bumps
and scratches is worth the same as m permanent brain damage'.

I'm not trying, I'm just looking at the headline serious injuries
and deaths and noticing nothing much happens as helmet wearing
rates change.

Quoted message said:

All the
statistics show is that number of deaths and serious injuries doesn't
significantly change; the statistics don't show whether there's a
systematic reduction in the number of 'injuries' which would never have
made it to a hospital anyway.

Precisely, so all we have with any reliability is the serious
stuff, and that doesn't change. So on balance your chances with a
hat of [not] having a serious injury are about the same with or
without a lid based on what we know.

What would be useful is to have a far finer grain of definition of
"serious", of course. One badly broken neck certainly doesn't
equate to one fairly nasty concussion. But without that fine grain
all we have is "serious" or "dead". And at that resolution,
helmets don't appear to change anything.

Quoted message said:

So I'm essentially leaving any systematic
reduction in scratches and bruises out of the equation, and just counting
deaths and serious injuries.

As am I. Non serious stuff isn't, well, /serious/, so will be
under reported in the data sets we have and therefore won't lead to
safe or reliable conclusions. So it should be ignored here.

Quoted message said:

If helmets cause (even very slightly) more
deaths than they save (which seems to be the case) then they're a bad
thing.

AFAICT the error bars on the total effect are at /least/ as big as
any effect good or bad you can really draw out from the data we
have. Bearing that in mind, I think saying they do nothing much
(that is 0 +/- a wee bit) is a much safer proclamation than
"slightly more deaths" (that is "a small though definite
disbenefit"😉. A plausible mechanism on its own isn't enough for a
safe conclusion.

Quoted message said:

If the number of deaths is not affected but helmets aggravate even
very slightly more permanent brain injuries than they ameliorate, then
they are a bad thing.

/If/ they do that, then yes. But the "if" is speculative AFAICT,
and cannot reliably be drawn out of any of the data I've seen. You
can't ignore the error bars.

Best to stick what you can be fairly sure about. IMHO that leaves
us with:
1) cycling not dangerous enough to warrant special protection;
2) if 1) was otherwise, EN1078 lids are basically irrelevant to
real safety and thus do not constitute "special protection". But
see 1).

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

Peter Clinch wrote on 29/04/2007 09:37 +0100:

Quoted message said:

AFAICT the error bars on the total effect are at /least/ as big as any
effect good or bad you can really draw out from the data we have.
Bearing that in mind, I think saying they do nothing much (that is 0 +/-
a wee bit) is a much safer proclamation than "slightly more deaths"
(that is "a small though definite disbenefit"😉. A plausible mechanism
on its own isn't enough for a safe conclusion.

I don't think that is correct. Rogers in the US, with statistics on 8
million cyclists found that "the bicycle-related fatality rate is
positively and significantly correlated with increased helmet use".

The Australian particularly and NZ longditudinal data on the number of
head injuries, the number of people cycling and the percentage wearing
of helmets across the introduction of mandatory helmets is more than
enough to demonstrate that the numbers wearing helmets increased
dramatically and the numbers cycling fell dramatically such that the
head injury rate increased signficantly. And that is just on the basic
data before you start factoring in other factors such as trends in other
groups such as pedestrian head injuries. The work of Hewson in the UK
shows similar results.

So a correlation between helmet wearing and head injuries has been more
than demonstrated in epidemiological studies. What has not been shown
is whether it is because of physical factors related to the helmet
wearing or psychological factors related to motorist and helmet wearing
cyclist behaviour.

--
Tony

"The most savage controversies are those about matters as to which there
is no good evidence either way."
- Bertrand Russell

In article <[email hidden]>,
Tony Raven <[email hidden]> writes:
|> Peter Clinch wrote on 28/04/2007 21:52 +0100:
|> >
|> > When you factor in the human side of it, in the current climate I'd
|> > agree they're bad on balance. But if (Ha!) the human side of it was
|> > sorted then I doubt it would matter whether or not folk wore them as far
|> > as safety went
|>
|> Even if they were completely neutral on safety ground they would be bad
|> on balance because the impression they give that cycling is so uniquely
|> dangerous that it requires special protective equipment. Just the
|> impression you don't need to encourage more cycling.

There is no evidence that the DfT wants to or is trying to do that.

Regards,
Nick Maclaren.

In article <[email hidden]>,
Tony Raven <[email hidden]> writes:
|> Peter Clinch wrote on 29/04/2007 09:37 +0100:
|> >
|> > AFAICT the error bars on the total effect are at /least/ as big as any
|> > effect good or bad you can really draw out from the data we have.
|> > Bearing that in mind, I think saying they do nothing much (that is 0 +/-
|> > a wee bit) is a much safer proclamation than "slightly more deaths"
|> > (that is "a small though definite disbenefit"😉. A plausible mechanism
|> > on its own isn't enough for a safe conclusion.
|>
|> I don't think that is correct. Rogers in the US, with statistics on 8
|> million cyclists found that "the bicycle-related fatality rate is
|> positively and significantly correlated with increased helmet use".

That doesn't mean quite what you seem to think that it means.

||> So a correlation between helmet wearing and head injuries has been more
|> than demonstrated in epidemiological studies. What has not been shown
|> is whether it is because of physical factors related to the helmet
|> wearing or psychological factors related to motorist and helmet wearing
|> cyclist behaviour.

What evidence there is, is that the physical factors related to helmet
wearing are nil to within the experimental accuracy, at least for all
normal forms of cycling. And the evidence for even a psychological
effect is VERY weak, except via the mechanism of discouraging cycling
(which puts up the risk).

Or that is what I found when I last looked.

Regards,
Nick Maclaren.