There's obviously been a lot of argument about the usefulness of helmets, though most of what I've seen here has just been "panacea vs. silly styrofoam hat" garbage.

My personal feeling is that the truth is somewhere between those two extremes (it usually is). Those who think they help prevent impact and abrasion injuries may have reason to think so. Those who think they may contribute to increased risk-taking (via risk homeostasis) and rotational injuries may also have reason to believe so. I don't hate on either side.

I'm not trying to convince anyone either way, but can anyone post evidence-based arguments for either side, please? Arguing via "common sense" won't do; that's just an assumption that's widely believed. Before I really thought about it, I felt sure helmets made me a lot safer. The animosity with which some on this board approach helmet use made me consider whether that is true. I still think they help in some instances, but I was wondering what the evidence is for either side. For example, is there any actual evidence for helmets increasing risk-taking or risk of a particular injury, or is that simply an assumed effect?

I'd like to have an actual discussion on this, rather than the insults we usually get out of it.

I'll start. The writers think helmets offer significant, though not perfect, protection in the event of an incident.