...I had an epic wreck when a horse flipped over a big fence on hard ground. I shatterd both forearms, cracked my right cheekbone and had a significant concussion, so much so that the rescue squad diverted en route and took me to a Level 1 trauma center. I was wearing the best helmet available at the time, a jockey's Caliente helmet. If you're reporting my case as a statistic in a study, do you report it in the 50% where the helmet failed to prevent an injury? Or is it in the category where the helmet greatly mitigated the effects of the fall...
I think it is given that helmets reduce the severity of many head injuries. However, from the viewpoint of someone trying to study equine safety, how do you measure that? There is never a way to determine precisely what would have happened if the person was wearing a ball cap instead.
I don't have professional access to the journals that involve safety, so I have to rely on free publications. The ones I have been able to find generally use around 50% reduction in head injuries.
Here is another challenge in discussing exactly how much safer someone is with a certain piece of gear:
Humans tend to judge total risk and reduce the total risk to a level they are willing to accept. On a given stretch of road, as cars handle better and become more safe, people respond by driving faster.
This is obviously true of gear and horses. I'm not the only one on this thread who has said he would never jump without a helmet. But jumping increases risk by some unmeasurable amount...yet I'll accept that risk, maybe, if I have a helmet, and will not if I do not. So how has my overall safety risk improved?
I have said I will probably never again ride my mare without a helmet. And the trails near where I live are so rocky and cactus-y that I doubt I'll ever ride ANY horse on the trails near here without a helmet. But that means the helmet makes me feel comfortable increasing my risk in another area because it has reduced my perceived risk of concussion.
I've brought statistics into these discussions to try to get away from pure anecdotal evidence. I think the broad trends that have been documented help people determine what is best for them.
Jumping statistics indicate an increased risk of 10X or possibly much greater. Proper gear, good horses, GOOD INSTRUCTION and other factors can reduce that risk, maybe even down to 1:1. But if someone doesn't know that jumping can be upwards of 10-80X more dangerous, they won't have a reason to mitigate that risk.
I think it is obvious that English saddles are less 'safe' than western or Australian saddles. After all, part of the design of western and australian saddles was a deliberate attempt to make them safer, while an English jump saddle is meant to improve the horse's jumping ability.
I have bookmarked an abstract that shows riding in an English saddle is associated with higher risk.
I own two English saddles, two Australian-style and one western. My favorite is the Bates Caprilli close contact. Although I've ridden Mia a lot of times with it, I probably will never do so again. However, I rode Trooper with it a couple of weeks ago. My conclusion was that I need to improve my riding at a canter and gallop some more, but I hope by spring to use that saddle as my normal saddle for Trooper in an arena. On the trails, it will be Aussie or western. With Mia, it will be western or Aussie, period.
We have a new pony. I ride Trooper and Mia primarily bitless, but the pony is new, nervous, and has never been ridden without a bit. So we will ride him with a bit until he calms down enough to try a rope halter only. And if it makes him nervous, we may only ride him with a bit forever.
That is the biggest point about riding safety that I want to make. The risk involves horse, rider ability and training, supervision, terrain, style of riding, saddles, bits/bitless, helmets, body protectors, etc.
And I think the biggest factor in riding safely is making an honest assessment - with an instructor's help, maybe - of your riding ability and horse, and accepting your limits. Use everything else to reduce the risk to a level acceptable to you. And if you cannot, don't ride that day.