Invisible Cyclists in Solstice Dark

[The Wogster]

gds wrote:
> Clive George wrote:
>
>>Um - no?
>>
>>If the total number of injuries severe enough to require hospital treatment
>>remains the same regardless of the fact that more helmets are being worn,
>>that indicates to me that wearing a helmet doesn't affect my chance of
>>getting seriously hurt in x years/km of cycling - the measure I mentioned
>>above as being the important one.
>>
>>The problem with the hypothesis you present above - that helmets make some
>>accidents minor and hence unreported - is that there doesn't appear to be a
>>corresponding reduction in the serious injuries suffered. If the number of
>>accidents remained the same, the helmets aren't working. If the helmets are
>>working, the number of accidents has gone up. Either way the chance of
>>getting a serious injury - which is as I may have said before, the only
>>important factor here - is not reduced.
>>
>
>
> Not quite! Despite prsentations on the effect of mandatory helmet laws
> and decreased ridership in some areas there is also separate data
> showing that, for example, in the US bicycle ridership has increased
> during the same time that helmet sales and use increased (no mandatory
> effect). Call it the Lance effect or whatever ( a few years ago it was
> the Greg Lemond effect). So, we also need to understand the
> denominator. If bicycle miles and/or time increased during the period
> in which helmet use increased you could have the result that the same
> number of serious accidents represented a smaller accident rate and you
> could hypothesize that the rate reduction was due to helmet use.

There are so many factors, that you can't take a specific factor in a
vaccuum when extrapolating gross numbers. For example mandatory helmet
laws (MHL), may reduce cycling by 30%, but the price of gasoline heading
over $1/L might raise cycling by 5%. Bike races, and other activities,
can also increase cycling by a percentage. Weather can also be a
factor, in nice weather, cycling could increase considerably over the
short term. A mild winter, could also mean a very long season, for
example I went for a ride on January 2nd, about a month later then I
would have expected to be able to ride.

A larger percentage of riders, using ride types like trail riding and
dirt jumping, could raise the number of injuries considerably, even
though the number of injuries of riders of more traditional types, could
be considerably reduced.

What is considered a head injury? For example do you include only
concussion on up, or do you include scratches and abrasions to areas of
the head that the helmet could not hope to protect you from, like a
facial scratch. Do you include non-head injuries?

Anyone who has taken a basic statistics course, will have seen how
numbers can be manipulated to say anything the statistician wants them
to (or is paid to have them) say.

W

 

[Tony Raven]

The Wogster wrote:
>
> Anyone who has taken a basic statistics course, will have seen how
> numbers can be manipulated to say anything the statistician wants them
> to (or is paid to have them) say.
>

And lots of people use that excuse to deny the statistical evidence when
it disagrees with their beliefs irrespective of the quality of the
statistics.

--
Tony

"Man is a credulous animal, and must believe something; in the absence
of good grounds for belief, he will be satisfied with bad ones."
- Bertrand Russell

 

[Sorni]

SMS wrote:
> Mike Rice wrote:
>>
>> 62% of people agree with this.
>
> Wait, at this point am I supposed to request that you cite a reference
> for this, or is it "surveys say that 62% of people agree with this"?

Well, first you have to factor-in Mike's propensity for rounding up 61.8% of
the time.

HTH, BS

 

[Tony Raven]

Sorni wrote:
>
> Well, first you have to factor-in Mike's propensity for rounding up 61.8% of
> the time.
>

And don't forget that rounded up to the nearest century that's 100% of
the time ;-)


--
Tony

"Man is a credulous animal, and must believe something; in the absence
of good grounds for belief, he will be satisfied with bad ones."
- Bertrand Russell

 

[geoffs]

Do you want the sensible answer as to why your argument is bollocks, or
shall I just ignore you since you're going to ignore anything anybody writes
against it anyway?

clive

The sensible answer that you are going to provide with your personal anecdotes ....................

Yes I will ignore that. Can't imagine why though

Cheers

Geoff

 

[Clive George]

"geoffs" <[email protected]> wrote in message
news:[email protected]...
>
> Clive George Wrote:
>>
>>
>> Do you want the sensible answer as to why your argument is bollocks,
>> or shall I just ignore you since you're going to ignore anything
>> anybody writes against it anyway?
>>
>> clive
>
> The sensible answer that you are going to provide with your personal
> anecdotes ....................

How about one not based on personal anecdote? (of course I can provide one
based on personal anecdote, but you didn't want that)

clive

 

[[email protected]]

gds wrote:
>
>
> Despite prsentations on the effect of mandatory helmet laws
> and decreased ridership in some areas there is also separate data
> showing that, for example, in the US bicycle ridership has increased
> during the same time that helmet sales and use increased (no mandatory
> effect). Call it the Lance effect or whatever...

.... which does not mean that helmet promotion and mandates had no
negative effect! IIRC, Australia's cycling count is now back up to the
level it was before the laws. Does this mean the law had no
discouraging effect? Hardly! Examining trend data, it's clear that it
would likely have been much, much higher without the helmet mandates
and promotion.

Note that I include promotion! Why? Because helmet promoters are
incapable of doing their sales job without heavily implying that
cycling is very dangerous. (After all, the average person doesn't
strap on a helmet for safe activities!)

As an example, look at the page Chris Street just gave us. Despite
quoting me at the bottom of the page, he's got about four screens of
graphs and text saying "Cycling... Casualties... Road deaths...
Accidents... Head injuries..."

The average non-critical reader glances at such a page. They don't
wonder "Hmm, how does this compare with other activities?" or "How
reliable is this data?" or "Should I be worried?" Instead, they think
"Whoa - I didn't realize cycling was that bad!!!"

Cyclists continually shoot themselves in the foot this way. By
comparison, the fatality rate for swimming is far higher, in either
absolute numbers or in fatalities per hour (roughly four times higher
according to one source). Yet when you talk to enthusiastic swimmers
or visit swimming websites, you don't get morbid counts of fatalities,
and you _certainly_ don't get nonsense like "Every swimmer should wear
water wings each time he swims!"


BTW, returning to the rise in cycling despite some American mandatory
helmet laws: Unlike Australia (where people have actually been jailed
for riding without helmets) the laws in America are widely ignored.
The do-gooders lobby hard to get them passed, they stand one compliant
cop up in front of the legislators to say how much good this will do
with how little effort, then they let the kids ride however they like.
In many jurisdictions, it's more a promotion gambit than a serious law
- and does a wonderful job of teaching kids that obedience to laws is
stupid.


>
> It seems to me that lots of you folks seem to oppose helmets stemming
> out the mandatory situation in some jurisdictions. I can sympathize
> with that sentiment. But I don't think the way to address it is to
> pretend you have good statistical evidence when you don't. I'm all for
> letting folks decide for themselves-- and Ijst wish everyone had much
> better data on which to base that decision.

Problem is, the data that gets trumpeted is _only_ the data that sells
helmets. Check ten helmet promotion websites today. See what figure
they quote as the benefit percentage. It'll be "85%" or "88%," the two
numbers given in the most infamously unrealistic promotion study.

Now try to find any jurisdiction where that prediction came true.

- Frank Krygowski

 

[[email protected]]

Mike Rice wrote:
> On Sat, 07 Jan 2006 03:58:36 -0800, SMS <[email protected]>
> wrote:
>
> >Mike Rice wrote:
> >
> >> No, I fear that any such proposed study is so inherently flawed that
> >> no good can ever come of it.
> >>
> >> Best to ask Robert and Steve up front and defer to their wisdom.
> >
> >Yes, that's the best option. Note that of course I have never stated
> >that cycling is unsafe, nor am I in favor of any sort of helmet
> >compulsion. What I don't like to see is the junk science used by the
> >anti-compulsion people, where they invent their own statistics, and try
> >to rationalize away all the studies regarding helmet benefits in the
> >event of head impact accidents.
>
> 62% of people agree with this.

If that's a sample statistic could you give us a confidence interval on
it?
John Kane, Kingston ON Canada

 

[[email protected]]

Tony Raven wrote:
>
> I've noticed a pattern in this thread which is whenever Scharf the Larf
> gets to a situation is sub-thread where his position is untenable,
> instead of accepting it he suddenly evaporates from that sub-thread and
> pops up elsewhere with a different argument.

In fact, that's exactly how this thread moved from a discussion of
headlights to a discussion of helmets, IIRC.

- Frank Krygowski

 

[[email protected]]

Tony Raven wrote:

> Right, which is probably a good point to draw a line under this thread
> given that the one thing that has been determined is that Robert and
> Steven are not interested in any answers unless it supports their faith
> in helmets.

Hey Tony,

I have no faith in helmets.

Please keep your wacky assumptions in check.

Robert

 

[[email protected]]

The Wogster wrote:
> gds wrote:
> > Clive George wrote:
> >
> >>Um - no?
> >>
> >>If the total number of injuries severe enough to require hospital treatment
> >>remains the same regardless of the fact that more helmets are being worn,
> >>that indicates to me that wearing a helmet doesn't affect my chance of
> >>getting seriously hurt in x years/km of cycling - the measure I mentioned
> >>above as being the important one.
> >>
> >>The problem with the hypothesis you present above - that helmets make some
> >>accidents minor and hence unreported - is that there doesn't appear to be a
> >>corresponding reduction in the serious injuries suffered. If the number of
> >>accidents remained the same, the helmets aren't working. If the helmets are
> >>working, the number of accidents has gone up. Either way the chance of
> >>getting a serious injury - which is as I may have said before, the only
> >>important factor here - is not reduced.
> >>
> >
> >
> > Not quite! Despite prsentations on the effect of mandatory helmet laws
> > and decreased ridership in some areas there is also separate data
> > showing that, for example, in the US bicycle ridership has increased
> > during the same time that helmet sales and use increased (no mandatory
> > effect). Call it the Lance effect or whatever ( a few years ago it was
> > the Greg Lemond effect). So, we also need to understand the
> > denominator. If bicycle miles and/or time increased during the period
> > in which helmet use increased you could have the result that the same
> > number of serious accidents represented a smaller accident rate and you
> > could hypothesize that the rate reduction was due to helmet use.
>
> There are so many factors, that you can't take a specific factor in a
> vaccuum when extrapolating gross numbers. For example mandatory helmet
> laws (MHL), may reduce cycling by 30%, but the price of gasoline heading
> over $1/L might raise cycling by 5%. Bike races, and other activities,
> can also increase cycling by a percentage. Weather can also be a
> factor, in nice weather, cycling could increase considerably over the
> short term. A mild winter, could also mean a very long season, for
> example I went for a ride on January 2nd, about a month later then I
> would have expected to be able to ride.

While this is true the Australian experience in particular makes some
of the alternative explanations less than completely plausible since
the implemenation of the MHLs was staggered by state so one has to
postulate that the same otherwise random causes occurred 'randomly' at
the same time as the helmet laws were instituted. [1] And then one has
to explain how the helmet laws had a positive effect in reducing
pedestrian injuries.



[1] IIRC the Commonwealth (i.e. Federal Gov't did some arm twisting
financially to get the states to buy into the law since apparently
traffic law is state not federal in Oz but the Feds had the money (Does
this sound familiar, at all?)


>
> A larger percentage of riders, using ride types like trail riding and
> dirt jumping, could raise the number of injuries considerably, even
> though the number of injuries of riders of more traditional types, could
> be considerably reduced.
>
> What is considered a head injury? For example do you include only
> concussion on up, or do you include scratches and abrasions to areas of
> the head that the helmet could not hope to protect you from, like a
> facial scratch. Do you include non-head injuries?

I don't think most of the Oz studies were that fine grained but the
hospital studies () typicially list the specific (standard
nomenclature) injury categories included in the study. TR&R being as
far as I can see an exception.

> Anyone who has taken a basic statistics course, will have seen how
> numbers can be manipulated to say anything the statistician wants them
> to (or is paid to have them) say.

However people with good stats/math skills (or, in many cases, just
good common sense and reasonable literacy ) can see where the tricks
are. That is one of the nice things about http://www.cyclehelmets.org/
.. They do excellent reviews of some of the papers and you can check
their comments out against the orginal papers and decide for yourself
if they are correct or not.

This, in essence, is much the way any research is done. You publish,
people read it and then the brawl starts. The problem is that while
a lot of the pro-MHL research is appallingly bad (not all by any means
but a lot) a lot of people accept the conventional wisdom and don't
bother to actually read the papers. Or think about exactly what the
results and figures really say. Or I suspect in some cases pretend to
have read the papers and write nonsense. For crappy nonsense read the
Canadian Academy of Sport Medicine's position paper on Mandatory Use of
Bicycle Helmets at
http://www.casm-acms.org/PositionStatements/BikeHelmets.pdf and then my
critique of it.http://ca.geocities.com/jrkrideau/casm_critique.pdf .


Also for an example not so much of bad research but a total inability
to understand that the results did not match their expectations have a
look at the study about the effects of a MHL in Nova Scotia: LeBlanc,
John C;Beattie, Tricia L; & Culligan, Christopher. (2002) Effect of
legislation on the use of bicycle helmets. Canadian Medical Association
Journal. 166, 592-595 available at
http://proquest.umi.com/pqdlink?ind...QT=309&VName=PQD&TS=1136658607&clientId=14119
Have a look at the first and last paragraph of the Results Section

>From the first para
n 1995/96, 1494 cyclists were observed on 17 days. In 1997, 636
cyclists were observed on 19 days. In 1998/99, 672 cyclists were
observed on 13 days.

>From the last para
A total of 416 bicycle-related injuries were recorded at the IWK Health
Centre in 1995/96, 222 in 1997 and 443 in 1998/99. Head injuries
accounted for 15 (3.6%), 3 (1.4%) and 7 (1.6%) of the injuries
respectively (p = 0.06).

The authos apparently did not even notice that the decrease in
cyclists was greater than the decrease in head injury rate.

Come to think of it we don't have to worry about numbers being
manipulated. Some of the authors seem likely to be unable to count
above 10 with their shoes on.

 

[[email protected]]

[email protected] wrote:
>
> The answer is likely this: A well-off Mommy in 1989 is so worried
> about "safety" that she puts a helmet on her kid, even though (at that
> time) only 3% or so of kids wear them. Then her precious angel falls
> and gets a scrape. What does Mommy do? Why, she rushes her baby to
> the ER "just to be sure"! After all, with the well-off insurance
> policy, it's free! And lo! "Your little angel if fine, ma'am. [Why
> did you waste our time???]"
>
> OTOH, the poor black single mom isn't able to afford a helmet for her
> kid, even with her employee discount at Wal-Mart. And she's not about
> to rush her boy to the ER for every scrape. For one thing, she has no
> medical coverage. So her boy gets taken there only if he's _really_
> hurt. "Sorry ma'am, but we recommend stitches in that ear so he
> doesn't get a scar. Now, do you have cash for the treatment?"
>
> If this sounds fanciful, keep in mind that D.L. Robinson (of the first
> paper) obtained the data set from the second study. She was able to
> "prove", using exactly the same calculation techniques with the same ,
> that the helmets "prevented" over 70% of leg injuries.
>
> And perhaps they did. Perhaps these hats really are magic!
>
> > In fact, there are good arguments to be made
> > against compulsion, but to deny the fact that helmets prevent injuries
> > and fatalities is not one of them.
>
> Despite the data, eh?
>
> - Frank Krygowski

To stress the point for some non-American readers one of the 'control'
groups (using the term very loosely indeed) came from a health care
group which implies a) typically higher income and b) private health
care coverage which combined means that a trip to the ER is of neglible
cost to the parent or child. The Case group is much less likely to
have health coverage and appears from the paper to be overall poorer.
Poor people who have to pay cash are less likely to rush to the ER for
minor injuries.

When you come right down to it the TR& T 1989 paper deserves to be
studied in most social reseach methods courses! The number of
egregious errors is astounding.
John Kane, Kingston ON Canada

 

[Dave Larrington]

In article <[email protected]>, Tony Raven (junk@raven-
family.com) wrote:
> Clive George wrote:
> >
> > (and then, where would I draw the line at recording accidents which
> > don't currently get recorded? slipping in the mud just after christmas
> > and sitting down sideways? Heck, I came off the bike - but I hardly even
> > got muddy.)
> >
>
> If its any help I chipped a fingernail cycling last year.

Mr Larrington's First Law Of Cycle Maintenance: any work involving the
chainset will result in at least one skinned knuckle.

Note to self: wear MartleHat while working on bike...

--
Dave Larrington - <http://www.legslarry.beerdrinkers.co.uk/>
We had that Maurits C. Escher in to do some building work once. I
haven't been able to leave the house since.

 

[gds]

Just zis Guy, you know? wrote:
> On 5 Jan 2006 13:04:02 -0800, "gds" <[email protected]> said in
> <[email protected]>:
>
> >I have also never had a response to my
> >question in this thread and others to point me to the studies that
> >address and solve the problem of non reported accidents.
>
> You can't measure them.

Yes you can! However it takes a proerly defined study to do so and not
just a retrospective look at data. Please acquaint yoursel fwith
population based epidemiological studies. There are whole sets of
emthodologies to address just this type of issue.

What you can do is compare the proportion of
> head and non-head injuries in those accidents which are reported.
> Logic dictates that if helmets are effective, there will be a change
> in the proportion of head to non-head injuries as the proportion of
> helmet wearing changes. And if you can find a single population where
> that has happened, you'll be doing better than Alistair Darling's
> civil servants could
>

But the "logic" dictates" argument is the same as the anecdotal
evidence argument you reject. "Logic" could also dictate the hypothesis
that helmets were so effective and ridership increased so that they
were preventing large numbers of accidents. Remmeber unlike your Oceana
data the US data is that ridership increased just as helmet use was
increasing. So without the data it is really hard to understand what is
happening overall.

Again, I don't know what the outcome of such a study would show. But
until the data on non reporting, that is non reported accidents and non
accidents are known all you are doing is inferring an effect from
incomplete data. That is not the same as a statisical extrapolation
from a proper sample.

 

[[email protected]]

[email protected] wrote:
> Tony Raven wrote:
>
> > Right, which is probably a good point to draw a line under this thread
> > given that the one thing that has been determined is that Robert and
> > Steven are not interested in any answers unless it supports their faith
> > in helmets.
>
> Hey Tony,
>
> I have no faith in helmets.
>
> Please keep your wacky assumptions in check.
>
> Robert

Robert's statement is consistent with his other postings. He's never,
AFAIK, said much in favor of helmets. That's not his point.

Robert's point has been that cycling is really, really dangerous.
Really. And if you have data that shows otherwise, it can't possibly
be correct, because cycling is really dangerous. Really.

;-)

- Frank Krygowski

 

[Ambrose Nankivell]

[email protected] wrote:
> [email protected] wrote:
>> Tony Raven wrote:
>>> Right, which is probably a good point to draw a line under this
>>> thread given that the one thing that has been determined is that
>>> Robert and Steven are not interested in any answers unless it
>>> supports their faith in helmets.
>>
>> I have no faith in helmets.
>>
>> Please keep your wacky assumptions in check.
>
> Robert's statement is consistent with his other postings. He's never,
> AFAIK, said much in favor of helmets. That's not his point.
>
> Robert's point has been that cycling is really, really dangerous.
> Really. And if you have data that shows otherwise, it can't possibly
> be correct, because cycling is really dangerous. Really.

He's right though. The error rate in cycling would not be tolerable in a
submarine or a nuclear power station.

For me, cycling is within an order of magnitude as dangerous as not cycling
(which makes me lose my appetite, eat poorly, sleep poorly, be miserable,
have Crohn's flare ups...). In other people, the mechanisms are different
(lack of motivation, obesity,...) but the increase in mortality is broadly
similar.

--
Ambrose

 

[[email protected]]

gds wrote:
>
> But the "logic" dictates" argument is the same as the anecdotal
> evidence argument you reject.

No. Sorry. There is a difference between "logic" and "anecdote."
Look them up!

> "Logic" could also dictate the hypothesis
> that helmets were so effective and ridership increased so that they
> were preventing large numbers of accidents.

Hmm. While you're poking around the dictionary, look up Occam's Razor.

What you're postulating is unlikely in the extreme - that at exactly
the same time helmet use increases, that ridership increases. Would
you pretend this happens in every jurisdiction, always perfectly
synchronized? What are the odds of that?

And you'd have to be implying that in the few places where counts of
cyclists were taken before and after helmet laws, those counts were all
wrong. What are the odds of that?

A final point. It's easy to see how mandating helmets, and spreading
propaganda that cycling is terribly dangerous, would cause a drop in
cycling. How would those things cause an increase in cycling?


> Remmeber unlike your Oceana
> data the US data is that ridership increased just as helmet use was
> increasing.

Not according to the New York Times article I posted earlier in the
discussion! They said the opposite was true.

- Frank Krygowski

 

[Tony Raven]

[email protected] wrote:
> gds wrote:
>
>> Remmeber unlike your Oceana
>> data the US data is that ridership increased just as helmet use was
>> increasing.
>
> Not according to the New York Times article I posted earlier in the
> discussion! They said the opposite was true.
>

Whatever is the opposite of Occam's Razor will probably now be invoked
by gds with parallel universes to reconcile his view of how this world
works with the conflicting data in the NYT.


--
Tony

"The best way I know of to win an argument is to start by being in the
right."
- Lord Hailsham

 

[Tony Raven]

[email protected] wrote:
>
> Robert's point has been that cycling is really, really dangerous.
> Really. And if you have data that shows otherwise, it can't possibly
> be correct, because cycling is really dangerous. Really.
>

Really?
;-)

--
Tony

"The best way I know of to win an argument is to start by being in the
right."
- Lord Hailsham

 

[gds]

[email protected] wrote:
>
> What you're postulating is unlikely in the extreme - that at exactly
> the same time helmet use increases, that ridership increases. Would
> you pretend this happens in every jurisdiction, always perfectly
> synchronized? What are the odds of that?


Not at all. I am not prtending it happens everywhere. But there have
been several periods over the past 20 years in which ridership in the
US increased. Most recently the "Lance" factor has had a noticable
impact. The last 20 years have also sen more helmet sales and use in
the US. So, this is a pretty big population to ignore. No?

And I'll offer another hypothesis. The increase in ridership is most
pronounced (% wise) among groups that even you will agree is on the
higer risk end of the cyclist population- namely mountain biking and
fast recreational riders. After all if we want to be like Lance we need
to buy an ultra light bike, have a nice racing kit, join a club and
ride fast in a pack.

>
> And you'd have to be implying that in the few places where counts of
> cyclists were taken before and after helmet laws, those counts were all
> wrong. What are the odds of that?

Over most of the US does there are no helmet laws effecting adults.
And adult ridership and helmet use have increased over the past couple
of decades.
>
> A final point. It's easy to see how mandating helmets, and spreading
> propaganda that cycling is terribly dangerous, would cause a drop in
> cycling. How would those things cause an increase in cycling?

Again, that has not been the expereince here in the US. Why do you keep
harping on the mandatory situation and what impact that has. I'm not
arguing that. In the US we have a huge example of increasing helmet use
of a non mandatory (at least governmental mandate, insurance for clubs
is a whole different matter) Why do you choose to ignore that.
>
>
> > Remmeber unlike your Oceana
> > data the US data is that ridership increased just as helmet use was
> > increasing.
>
> Not according to the New York Times article I posted earlier in the
> discussion! They said the opposite was true.


And like everything else in this debate there are also citations to the
contrary.

Wouldn't it be nice to have a good study so we could actually know.