Originally Posted by sudo bike

Precisely. njkayaker looks at the chart I posted and says "well yeah, but there may have been some effect because it dropped a bit after use rates increased in the 80's". Ignoring the fact that it was, on the whole, a continuing downward trend for quite awhile, the real telling part is that coupled with that decrease which was already trending, there was an exponential increase in helmet use, with no correlating decrease in deaths. I mean, use skyrocketed. If helmets were even halfway as effective as the most virulent believers claim, there should have been more effect, and a more undeniable effect. Certainly not an arguable blip occurring during a downward trend.

Now, look at the oft-touted comparison of seatbelts, and look what we get:





Seatbelts have a distinctly more noticeable, and pretty undeniable effect. I had a harder time finding motorcycle helmet uses, but they also seem to have a better reflection than bike helmets do:



Much more of what you would expect to see from what is designed, tested, and used as a life-saving device. At the very least, this should make clear that even if helmets are effective to a degree, they are not nearly as effective as is commonly believed, and are far from a panacea (I realize not everyone or even most on here are arguing this, but it is commonly treated that way in practice, for better or worse).