Originally Posted by
Drwecki
Since the majority of crashes don't involve the head including all the crashes that don't involve the head leave you with low statistical power (the ability to see a significant difference if one exists).
Well, if crashes are rare, and the majority of these rare occurances don't involve the head anyway, then the only sane conclusion is that it doesn't really matter if people wear helmets or not. For example, what if it were merely true that for every 1 million uses of helmets, a handful of head injuries would be reduced in severity. If such a thing is true, then it's hardly even worth thinking about helmets at all, much less wasting time promoting or requiring them, especially if doing so leads to a drop in cycle usage overall (as it did in Australia and is currently doing in Copenhagen: see the story in latest issue of
http://www.citycycling.co.uk/).
The second thing is that this is a public safety question and classic philosophers say that public safety and lives should not be gambeled with, thus we should do the safe thing (wear a helmet) until data disproves that helmets are effective.
But to do so would be to totally ignore your goal: public safety. Not because helmets have been proven to be ineffective, but because promoting or requiring helmet usage has been proven to decrease bicycling, leading to a net loss in public health that no amount of head protection gained from wearing helmets could match.
Besides, if we have to wear all safety gear until it's proven ineffective, then we might as well wear full american football gear for walking down the street. We'd better wear racing safety harnesses and HANS device head protection and helmets in our cars. Etc....