Wanlock Dod wrote:I have often wondered why given all of the demonstrable benefits of cycle helmets they don’t seem to be able to actually make cyclists safer in real world situations, can you offer any insights into why that might be?
Because you are analysing the wrong data.
I'm reminded of the expression "garbage in, garbage out" so often when looking at studies that supposedly prove cycle helmets protect. Of course if someone fixes the data first, they can prove anything: figures can't lie but liars can figure, like the proverb says.
poetd wrote:A helmet cannot prevent an accident occuring. There's no reason to think it would.
If you measure by that standard, then it's easy to prove that helmets have no effect.
But the converse is true: clearly a helmet can cause a crash (not accident, please - most of the data includes the reasonably forseeable crashes too). In the extreme case, a loose helmet falling forwards and covering the eyes can cause the rider to crash. Surely you can at least agree that?
However, the vast body of research out there shows that helmets DO help to reduce the severity of head injury.
If we measure by that standard - then enforced legislation starts to look downright common sense - which is of course why anti-helmet advocates refuse to acknowledge that data.
That's a misleading standard. The vast body of helmet-favouring research mostly repeatedly shows that helmets probably help a little IF someone crashes, which is something few dispute. What they do not show is whether helmets help without the conditional - in other words, that helmet use improves outcomes - and that's what we care about, the outcomes of the whole population, not only mitigating the subset that crash.
If we can reduce the size of the subset that crash - reduce the number of crashes, bluntly - then that will dwarf the effect of cycle helmets... and if cycle helmet use causes more crashing, as many studies suggest, then it makes more sense to ban them, like banning F1 motor racing helmets and collars from driving on the grounds of restricting hearing and vision.
Analysis of the crude, unadjusted data showed a statistically significant association between helmet use and reduced severity of head injury
The injury data in that one does not seem to contain helmet use. While falling head injury rates may correlate with growing helmet use in that case (and helmet use data is in another paper I have not even glanced at), both correlate with time (of course) and no causal link is shown. It seems strange that the researchers grasp at the helmet straw as the sole "probably" to cause the head injury rate reduction.
Researchers found that people wearing helmets had 52 percent lower risk of severe TBI, compared to unhelmeted riders, and a 44 percent lower risk of death.
Riders with helmets also had 31 percent lower odds of facial fractures. The upper part of the face, particularly around the eyes, was most protected
No citation, unverifiable. Sorry for not hunting it down.
These data demonstrate that lack of helmet use is significantly correlated with abnormal head CT scans (fractures), admission to the hospital, admission to the ICU, and overall worse TBI severity both in the prehospital and ED environments
Mixes up 143 bicycle riders among their 478 injured people. The cyclists are 73% male and median age 26, which is even more skewed to young males than the cycling population. 50 of the 143 injured cyclists were off-roading. It seems a stronger argument for being older, female and staying on-road than for using a helmet.
As ever, studying only injured people is flawed because it tells you nothing of whether helmet use makes an injurious crash more likely.
Most bicycle-related accidents with head injuries (70%) happen without the involvement of motor vehicles (single accidents), but this study shows a decrease in head injuries also in collisions with motor vehicles. It also shows a decrease in both concussion and skull fracture.
Showing a protective effect beyond the design limits of the helmet clearly calls the study methodology into question. It is not quite as conspicuous as the study with the data that suggested that helmet use protects your arms and legs, but it still seems pretty incredible and suggests something other factor at work.
The team found cyclists without helmets were 5.6 times more likely to suffer any head injury than cyclists wearing a helmet and 5.5 times more likely to suffer a severe head injury.
No citation, unverifiable, but I strongly suspect this was another study that actually found cyclists that crashed without helmets were 5.6 times more likely [...] than cyclists that crashed wearing a helmet (and so on). The "that crashed" so often gets lost in reporting of these studies and it is a very very big conditional which changes the nature of the study population entirely.
So it's not like the benefits aren't measured and known, you're just chosing to ignore them in favour of other cherry-picked data which supports your position.
That seems very similar to ignoring the flaws in the above studies and misrepresenting them by omitting words like "that crashed" and "probably" from the results - why did you choose to do that?