> The most reliable estimates indicate that at speeds of up to 20 km/h helmets reduce the risk of head injury by 42%, the risk of brain injury by 53%, and the risk of facial injury by 17%, whereas they increase the risk of neck injury by 32%. These estimates are partly based on research carried out in countries like the United States and Australia, where standards for bicycle helmets are stricter than they are in Europe and can offer protection at higher impact speeds.
In wikipedia [2] I find this quote: "This effect is statistically significant in older studies. New studies, summarised by a random-effects model of analysis, indicate only a statistically non-significant protective effect"
And to the parents around here, make sure your kids know when to not wear a helmet (choking accidents [3])
[1] https://www.helmets.org/stats.htm#effectiveness
[2] https://en.wikipedia.org/wiki/Bicycle_helmet#Effectiveness
[3] https://en.wikipedia.org/wiki/Bicycle_helmet#Accidental_hang...
Typical fall has the first contact either direct front or direct back based on kinematics which means they're subject to most force. Falling on side of head is somewhat more rare. Falling on top of the head is rare.
At least we usually figure it out. "More injuries because less deaths" is simple enough, I guess.
In the only serious bike accident I have been involved in, the victim would have walked home on their own feet had they worn a helmet. Instead, a fall from the bike on low speed and hitting their head on tarmac ended up in serious head injury and 6 months in the hospital.
Had they walked home, it would have not ended in the stats.
The helmet literally saved my life.
I don't think this phrasing makes sense. A particular study may find a positive effect but with p>0.05, but that depends as much on the size of the study as on the effect itself.