The CycleChat Helmet Debate Thread

[srw]

Perhpas I should have said helmet wearing is increasing from 1984, although I thought ut was pretty clear that was what I meant, apologies for not being clearer. Yes there is important data markers missing from the graph, however it was introduced to show that wearing a helmet didnt reduce the number of head injuries while that is one thing it most definitely doesnt support.

Oh, one more thing - and my final word on the topic for the moment, I promise.

There's a well-known psychological phenomenon that we're all prone to called confirmation bias. I would suggest that you and I, in our initial responses, both illustrated it well. Confirmation bias is the tendency to exaggerate the strength of evidence for positions we support, and diminish the strength of evidence for positions we don't. I chose to ignore the tiny association between reduced cycling head injury and increase in helmet wearing in the early years; you chose to ignore the non-existent association between the massive increase in helmet wearing and the flat-lining of the cyclist head injury curve.

In my defence, even allowing for the occurrence of confirmation bias, I think my error was the less egregious - because there is a seriously strong association between the reductions in cycling and pedestrian head injury, which essentially wipes out any association between what headgear cyclists wear and what happens to their heads. Unless you're going to argue that cyclists wearing helmets has a prophylactic impact on pedestrians' skulls when they have a head injury?

And I'll come back to what I said before - the graph is useless without an explanation of what "rate" of head injury is being measured. As it stands, I feel like reporting the person responsible for publishing the graph to Southwark Trading Standards for false advertising...

 

[mjr]

When it comes to cycling head injuries what does it matter what causes head injuries in an unrelated activity to fall?

Walking and cycling are both ways of getting from A to B and mostly involve the same road and track environment, especially for an injury to get recorded as a pedestrian" injury in most places, although we can't be sure for that under labelled graph. But they are related activities, so your deducted scenario is possible but seems improbable because it doesn't explain the decrease in pedestrian head injury rate as well as many alternative theories.

 

[doog]

Walking and cycling are both ways of getting from A to B and mostly involve the same road and track environment, especially for an injury to get recorded as a pedestrian" injury in most places

Perhaps things have changed but that wasn't my experience. If they weren't in a car, bus on a horse or cycle they were simply listed as pedestrian no matter where they were. I'm also struggling to see the link between pedestrians and cyclists in relation to head Injuries bearing in mind the majority of pedestrian falls are the elderly, drunk or infirm / ill. If the argument was that elderly should wear lids I could understand it but simply portraying the general pedestrian population as a comparison to cyclists is completely flawed in my opinion.

 

[doog]

Just back from a five week tour; I was surprised at the number of people wearing helmets in Germany, I'd say 75% of riders we saw on segregated cycle routes (mostly bimbling along) were

I found the same last year . The odd thing is that the author of this recent report in Germany stated 9 out of 10 cyclists don't wear a helmet. It was a report that supported non compulsion in its findings incidentally http://www.cycle-helmets.com/germany-helmet-law-cost-analysis-2014.pdf

Irrespective of the findings it does make you wonder how accurate reports such as these are. Someone recently mentioned they would support data over experience, perhaps the author of this report should get out and cycle around Germany.

That aside, no one in Germany questioned my choice of head wear, no gasps of amazement, the only grief I got was from a motorist as I cycled up the wrong cycle path against the flow of traffic.

 

[Tin Pot]

In a word, yes.

In a word, yes.

Demonstrably, the risk of serious injury while walking is similar to that while cycling. The risk of serious injury while skiing is far higher than that while cycling.

When I cycle, people ask whether I'm going to wear a helmet, and tell me off or gasp in amazement when I say no. When I say I'm going for a walk they say "have a nice time". When other people say they're going skiing they are wished a nice holiday. I'm in the minority in wishing others a safe, injury-free holiday.

You know there a whole swathe of skiers who refuse to wear helmets that argue with the pro helmet guys too?

 

[mjr]

Perhaps things have changed but that wasn't my experience. If they weren't in a car, bus on a horse or cycle they were simply listed as pedestrian no matter where they were.

I'm 90% sure that if no other vehicle is involved, a pedestrian fall won't show up in road traffic casualty statistics in many counties. Is your experience Australian and what is it?

 

[Wobblers]

Personally the stats for pedestrians are irrelevent to me when considering whether to wear a helmet when cycling.

The graph does appear to show that the increase in helmet wearing corresponds with a fall in head injuries. Although there could be other contributory factors such as safer cycling infrastructure.

Nope.

That graph shows a surprisingly strong correlation between the (irritatingly undefined) "rate" of cyclist and pedestrian head injuries. This is suggestive that both share some process - collision with vehicles would be a reasonable supposition.

What is does not show, at all, is any correlation between the fraction wearing helmets and head injury rate. If, during the line of my work, I produce a similar looking data, I move onto something else, because I've just demonstrated to a high (publishable) standard that there's no link between both measured variables.

 

[ufkacbln]

Perhaps things have changed but that wasn't my experience. If they weren't in a car, bus on a horse or cycle they were simply listed as pedestrian no matter where they were. I'm also struggling to see the link between pedestrians and cyclists in relation to head Injuries bearing in mind the majority of pedestrian falls are the elderly, drunk or infirm / ill. If the argument was that elderly should wear lids I could understand it but simply portraying the general pedestrian population as a comparison to cyclists is completely flawed in my opinion.

Any more flawed than treating the general population of cyclists as a single group?

Is the person pootling 200 yards tat 10 mpho the shop at the same risk as the racer travelling at 50 mph in a close peleton?

The "drunk, elderly, and infirm" are the high risk equivalent of the racing scenario

Pedestrians as a comparison are important as they show many of the flaws, and hypocrisies in the pro-compulsion lobby

 

[MontyVeda]

When it comes to cycling head injuries what does it matter what causes head injuries in an unrelated activity to fall? There is simply no data to make any judgement on pedestrian head injuries and it is not particularly relevent. The graph shows a rise in helmet use since 1984 and a corresponding fall in head injuries from 1985 onwards, it is an imperfect graph as we have no idea what the %age refers to. All we can deduce is that increased helmet wearing appears to have been followed by a decrease in head injuries, we can only surmise if the fall in head injuries is due to helmet use, there may and oprobably is other contributory factors, we simply do not know.

well... it shows a decrease in head injuries for two different activities, so it matters, it's on the graph.

 

[Wobblers]

who knows but as its a completely different activity its not particularly relevent to cycling, just as the stats for helmet wearing while skateboarding, skydiving and potholing are not particularly relevent.

Again, no. The data shows a strong correlation between the rate of decrease of pedestrian and cyclist head injuries. Any scientist looking at that data will come away wondering just why is there such a good correlation between both groups, as this (provided that the correlation is statistically significant, it looks like it is, but I'd need to see the raw data to establish that). The reasonable starting point is to determine what elements are common between both groups. The one common thing between both cyclist and pedestrian is that collision with vehicles is a major cause of head injury. If it were me, that's where I'd be looking to explain this.

 

[ufkacbln]

Again, no. The data shows a strong correlation between the rate of decrease of pedestrian and cyclist head injuries. Any scientist looking at that data will come away wondering just why is there such a good correlation between both groups, as this (provided that the correlation is statistically significant, it looks like it is, but I'd need to see the raw data to establish that). The reasonable starting point is to determine what elements are common between both groups. The one common thing between both cyclist and pedestrian is that collision with vehicles is a major cause of head injury. If it were me, that's where I'd be looking to explain this.

One of the other "anomalies" of the Australian helmet debacle, and the unexplained failure of compulsion to significant decrease head injury is that the time it was part of a whole raft of measures including a clampdown on speeding, drink driving, unroadworthy vehicles, dangerous and inconsiderate driving.

Another reason to question why the decrease in head injuries was slowed by compulsion

 

[benb]

Anyone who can, with a straight face, claim that that graph shows or even suggests that helmets reduce head injuries doesn't understand graphs, data, or stats.

What it quite clearly demonstrates is that there is a massive spike in helmet wearing rates but no corresponding decrease (above the existing downwards trend) in head injury rates.

 

[Tin Pot]

Anyone who can, with a straight face, claim that that graph shows or even suggests that helmets reduce head injuries doesn't understand graphs, data, or stats.

You are posting to a vast population of straight faces.

 

[snorri]

Just back from a five week tour; I was surprised at the number of people wearing helmets in Germany, I'd say 75% of riders we saw on segregated cycle routes (mostly bimbling along) were,

I also noticed this among tourers on the paths, the majority with brand new cycle clothing, panniers etc., but did not see the same high levels of usage among utility cyclists there.

 

[Big Andy]

Unfortunately, after last night's ride, I now have some first hand experience when it comes to wearing a helmet and head injuries. Had a spill yesterday, bit of a freak incident, on a bend on the flat at about 10-12 mph. Back end skidded out on a slippy patch, landed heavily on my right hand side and back, right hand side of head hit quite hard too. Was wearing a helmet which is now cracked and will be going in the bin and getting replaced. Went to AnE as it was very painful to breathe an hour or so later and I thought I may have damaged ribs. Few other cuts and bruises. Xray showed no rib damage so looks like just soft tissue damage only, still painful on my right hand side and back.

This is the helmet damage, some crushing and a crack if it can be seen.


Did the helmet prevent a head injury? My head hit quite hard and while obviously the helmet makes your head a bigger target I think it would probably have still hit quite hard, there is no way of knowing if I would of sustained a head injury without the helmet or how bad it would have been but I suspect the helmet has in this case served its purpose.