Hemlet Safety Study flawed - SMH

[Westgarth]

Hope I don't get nuked for posting this

(One wonders whether the fact that academics who make such errors and who don't support compulsory wearing of bike helmets is perhaps linked )

http://www.smh.com.au/national/authors- ... 19a9x.html

Authors admit errors in study on bike helmets and head injuries
Matthew Moore
December 30, 2010

TWO academics have apologised for publishing a study which said compulsory helmet laws for cyclists did not reduce head injuries after a critic identified errors in their research.

Associate Professor Chris Rissel, from the University of Sydney's school of public health, and Alex Voukelatos conceded they had made arithmetic errors in their peer-reviewed article, published in the August issue of The Journal of the Australasian College of Road Safety.

In the latest issue of the journal, the authors concede a number of mistakes identified by a medical epidemiologist, Dr Tim Churches, who challenged their finding that laws introduced across Australia in 1991 were not responsible for a fall in head injuries.

''Churches is quite correct in writing that the paper … has serious arithmetic and data plotting errors,'' they wrote in the latest issue.

''We sincerely apologise for these unintentional errors and any confusion that this may generate.''

Dr Rissel said the mistakes resulted from ''transcription errors'' from repeated computer runs to generate the data used in the study, while ''data plotting errors'' in the graph were a result of re-scaling of the graph without adequate checking of the positioning of the added figures.

When advised of the mistakes, he said he had obtained additional data from Western Australia and Victoria which confirmed the original findings that general improvements in road safety before the compulsory helmet laws were behind the fall in head injuries among cyclists.

''Our original conclusion is quite reasonable,'' he said.

He is hoping to publish his additional research in the same journal early next year.

In his original study, Dr Rissel analysed the ratio of head injuries to arm injuries among cyclists admitted to hospital between 1988 and 2008. He assumed the ratio would not change unless helmet use reduced head injury rates compared with arm injury rates.

Dr Churches said no such conclusions could be drawn from the study because of the errors.

While Dr Churches said he would wait to see what the additional research might say, he believed compulsory wearing of helmets had helped to reduce head injury rates.

''It is now clear that the Voukelatos and Rissel study provides no new impetus for the Australian cycling helmet laws to be repealed,'' he said.

''There's nothing in that data which suggests the legislation did not have an impact.''

[TheSkyMovesSideways]

(One wonders whether the fact that academics who make such errors and who don't support compulsory wearing of bike helmets is perhaps linked )

One wonders whether the fact that conspiracy theorists who deny climate change, deny the moon-landing, deny the holocaust, etc and who support compulsory wearing of bike helmets is perhaps linked. <sic>

[simonn]

Yes yes, confirmation bias. This is why we have the scientific method, which we see demonstrated here - scientists provide evidence of X which is challenged by another scientist etc.

Science. It works! (tm)

[sogood]

One wonders whether the fact that conspiracy theorists who deny climate change, deny the moon-landing, deny the holocaust, etc and who support compulsory wearing of bike helmets is perhaps linked. <sic>

Actually, one wonders whether the fact that conspiracy theorists who deny climate change, deny the moon-landing, deny the holocaust, etc and who are trying to repeal compulsory wearing of bike helmets is perhaps linked. <sic>

[Westgarth]

Start a seperate moon landings are real thread - I dare you! You'll look so silly..... well, actually you already look pretty silly.

[trailgumby]

The question is not whether helmets reduce injury rates or not - it is clear that they do.

The issue is whether the societal costs of legal compulsion - reduced participation and exercise rates, poorer health due to inactivity, increased pollution due to greater congestion from increased motor vehicle use in our cities, consequent impact on health care costs and loss of quality of life - are greater. I believe they are.

[sogood]

The question is not whether helmets reduce injury rates or not - it is clear that they do.

The issue is whether the societal costs of legal compulsion - reduced participation and exercise rates, poorer health due to inactivity, increased pollution due to greater congestion from increased motor vehicle use in our cities, consequent impact on health care costs and loss of quality of life - are greater. I believe they are.

That indeed is the point.

But it's also relevant to consider the fact that there are many other forms of exercise/health inducing transport other than cycling eg. Walking, jogging, bus+jog, train+jog etc, so the societal effect is not solely dependent on cycling. While when one is on a bike, helmet is the only piece of safety equipment. It may not have an effect on the incidence of accidents, but is designed to reduce the severity of head injury when it does happen. And with the data collection methods used in most of these studies, it's no surprise there's little or no demonstrable effect. And for those who have head planted onto a gravel road at high speed and walked away without scalp loss, the benefit is pretty obvious.

[trailgumby]

That indeed is the point.

But it's also relevant to consider the fact that there are many other forms of exercise/health inducing transport other than cycling eg. Walking, jogging, bus+jog, train+jog etc, so the societal effect is not solely dependent on cycling.

You seem to be implying that the downturn in cycling attributable to helmet compulsion (thanks for acknowledging that by the way) has been offset to a significant degree by people taking up other forms of self-propelled transport or other exercise.

Where's the evidence for that?

While when one is on a bike, helmet is the only piece of safety equipment. It may not have an effect on the incidence of accidents, but is designed to reduce the severity of head injury when it does happen. And with the data collection methods used in most of these studies, it's no surprise there's little or no demonstrable effect. And for those who have head planted onto a gravel road at high speed and walked away without scalp loss, the benefit is pretty obvious.

You're disputing an argument I haven't made. I agree with you on this one. They do reduce injuries. But making them compulsory also keeps people off bikes for transport, as you are acknowledging.

The other question I would like to put to you is why you think other jurisdictions who have recently considered compulsory helmet laws have used the Australian and NZ experience as justification for staying away from making them compulsory? Italy is just one recent example.

[sogood]

You seem to be implying that the downturn in cycling attributable to helmet compulsion (thanks for acknowledging that by the way) has been offset to a significant degree by people taking up other forms of self-propelled transport or other exercise.

But that's how the anti-helmet brigade has used that data to argue their cause, as if the populace will die through a lack of cycling... One adversely influenced by enforced wearing of cycling. At the end of the day, that's all historic data and there were too many material/social/economic variables that are no longer in play right now. What's important is what makes sense in 2010 and moving to 2011 and the future. Helmets comfort has improved dramatically since those early stack hats, environmental and economic priorities has changed, so the society has moved on. Over emphasising a statistical observation from decades past is clutching a rotting straw.

The other question I would like to put to you is why you think other jurisdictions who have recently considered compulsory helmet laws have used the Australian and NZ experience as justification for staying away from making them compulsory? Italy is just one recent example.

"Democratic" decisions are not necessarily scientific nor logical. And given the foreign set of circumstances (Italians at that), it's not that relevant.

[Westgarth]

Over emphasising a statistical observation from decades past is clutching a rotting straw.

This is the most insightful thing I've ever heard someone named after mock-icecream say.

[sogood]

This is the most insightful thing I've ever heard someone named after mock-icecream say.

Some statements lack foundation.

So Good the soya drink has no need to mock. It's but a standalone beverage that has been around for thousands of years <http://en.wikipedia.org/wiki/Soy_milk>.

[trailgumby]

Yes, observation of the cycling population growth charts demonstrates that it was a once-off hit several decades ago. Equally those charts demonstrate that the growth in cycling participation rates have never recovered from the setback.

The reasons for being turned off cycling by helmets have not changed:
* Implication that cycling is somehow dangerous, otherwise why mandate helmets?
* Hassle to carry around a helmet
* Still makes you sweaty, despite the notable improvements
* Makes a mess of your hair

The above hassles bother me not in the slightest as an enthusiast, but for the general public for whom a bike is one transport option among many, they serve to place a barrier in front of bicycling for utility purposes.

Listen, I'm not anti-helmet. I'll continue to wear one, regardless of the law.

However, on this matter I go where the facts lead me. I used to be pro-compulsion. I find the evidence pointing to the high cost of the unintended consequences of this law pretty compelling. Short term gain for much greater long-term pain.

[trailgumby]

Democratic" decisions are not necessarily scientific nor logical. And given the foreign set of circumstances (Italians at that), it's not that relevant.

Actually, in this case, it was the democratic process that got the movement towards MHL rolling. An Italian Parliamentarian, I believe. It was the public policy bureaucrats that scuppered it by providing evidence that it would result in a significant hit to the public purse through the net impact on community health being much worse over the long term.

Just becasue an experience is offshore, does not mean it's irrelevant. You work in health sciences do you not? Does our medicines authorisation body replicate every bit of drug testing before medicines are approved here? Sometimes they do, but mostly not. Offshore experience provides significant guidance in fact.

Clearly, though, this experience is unwelcome to your case.

Edit: And now that I stop to unpack your statement a little further, your disparagement of the Italians strikes me as quite racist.

By the way, they're not the only country to make this public policy decision based on what they've seen happen to us, only the most recent.

[sogood]

The reasons for being turned off cycling by helmets have not changed:
* Implication that cycling is somehow dangerous, otherwise why mandate helmets?
* Hassle to carry around a helmet
* Still makes you sweaty, despite the notable improvements
* Makes a mess of your hair

There indeed are risks associated with cycling, and anyone with any brain cells can work that out without even considering helmets. As a matter of fact, sensible people will understand "speed = risk" and helmet wearing is a sensible and responsible equipment for the activity.

Fortunately short hair remains in fashion and suits our Australian climate, and helmet wearing. Whilst wind blown hair is as messy as helmet hair for those with fancy hair dos, so again that's an trivial issue.

[sogood]

Just becasue an experience is offshore, does not mean it's irrelevant...

But on a parliamentary decision that related to local customs, special interest groups, science and technologies, it's not particular relevant. Just as the Italians repeatedly votes for Berlusconi does not mean we'll need to consider one of the Packer, Lowey or Forrest at our next election. We can consider what is relevant in our decision and there's no need to bringing in the Italians.

As for those "projected" health economic benefits. Well, how many of those projections circulating in scientific and government circles have been found to follow their exact projection? I'd take a discount on them on the basis of "potential". But the energy absorption function of helmets and the relationship b/n energy and brain injury are hard scientific facts.

[biftek]

As a gym user you tend to notice a thing or two about people when it comes to hard work , if there is an easier way about it the masses will take that option
Any person that is a gym rat will tell you that around the same time every year , just when the warmer weather starts hitting the gym gets a sudden influx of people wanting to buff up , however when they find that to buff up takes a lot of effort and hard work they will walk away from it

the same can be said for cycling , it's too much hard work to cycle to places when there is far easier options like the car/bus/train , you can put any spin you want it saying that it's the helmets that turn people away , the fact is helmets have been law for 19 years and people are lazy

the perception is that cycling isn't dangerous but much rather that the streets are dangerous , look at all the soccer mums that drive their little darlings to school in fear that some child molester is going to abduct them off the side of the road

people will look for any excuse to get out of hard work

[trailgumby]

Yes, sogood it is trivial. All of it, not just the windblown hair.

Doesn't stop non-enthusasts being turned off by helmets though.

[sogood]

Edit: And now that I stop to unpack your statement a little further, your disparagement of the Italians strikes me as quite racist.

Not at all. Just stating that the Italians think differently and have different electoral criteria, as evident by their support for Belusconi, Cicciolina amongst other elected politicians. So their parliamentary decisions need not be considered for Australian circumstances.

Maybe a more effective way to revoke our helmet law is to actively campaign for similar politicians here in Australia.

[sogood]

Yes, sogood it is trivial. All of it, not just the windblown hair.
Doesn't stop non-enthusasts being turned off by helmets though.

Non-enthusiasts will use any excuse to justify their turn-offs, especially those flagged by anti-helmet lobbists.

[Aushiker]

Hi

With reference to the headline/subject line, there where transcribing errors in study, however that does not make it "flawed" as claimed, i.e., the authors still believe the data supports the conclusion.

When advised of the mistakes, he said he had obtained additional data from Western Australia and Victoria which confirmed the original findings that general improvements in road safety before the compulsory helmet laws were behind the fall in head injuries among cyclists.

''Our original conclusion is quite reasonable,'' he said.

Andrew

[mikesbytes]

(One wonders whether the fact that academics who make such errors and who don't support compulsory wearing of bike helmets is perhaps linked )

I've never seen Chris Rissel ride a bike without a helmet on

[trailgumby]

Just becasue an experience is offshore, does not mean it's irrelevant...

But on a parliamentary decision that related to local customs, special interest groups, science and technologies, it's not particular relevant. Just as the Italians repeatedly votes for Berlusconi does not mean we'll need to consider one of the Packer, Lowey or Forrest at our next election. We can consider what is relevant in our decision and there's no need to bringing in the Italians.

As for those "projected" health economic benefits. Well, how many of those projections circulating in scientific and government circles have been found to follow their exact projection? I'd take a discount on them on the basis of "potential". But the energy absorption function of helmets and the relationship b/n energy and brain injury are hard scientific facts.

If that statement about Lowy et al is meant to be evidence supporting the first statement, I have to admit you're losing me my friend.

Same with the quip about the energy absorption function of helmets. Not because it isn't a hard fact, but because for the second time you've trotted it out like I disagree with you!

Seems like you're not capable of engaging with what I'm actually saying to you. Very well. Carry on.

[rkelsen]

Not at all. Just stating that the Italians think differently and have different electoral criteria, as evident by their support for Belusconi, Cicciolina amongst other elected politicians. So their parliamentary decisions need not be considered for Australian circumstances.

What a bizarre statement! Italians are people too. Sure, their elected officials may not meet your criteria for good leaders, but that does not mean that they are incapable of making good decisions. From my angle, John Howard was a poor leader as well... but the man ran the country for 10 years whether I liked it or not.

Yes, Berlusconi continues to make some terrible decisions in his personal life, but there is a reason that he has been PM for 9 of the last 64 years (a period which has seen Italy change its Prime Minister 40 times).

You should speak to an Italian one day.

[jules21]

Yes, Berlusconi continues to make some terrible decisions in his personal life, but there is a reason that he has been PM for 9 of the last 64 years (a period which has seen Italy change its Prime Minister 40 times).

indeed. it's his virtual control of the national media, which has provided saturation coverage of his 'achievements', while succeeding in effectively silencing his critics. such an arrangement would be completely illegal in any genuine democracy, such as australia. he is a crook with established links to the mafia.

[Westgarth]

Yes, John Howard is notorious!