On 1/19/2020 11:38 AM, Frank Krygowski wrote:

Bicyclist concussions have gone up, way up, over the last decade
just as helmet use continued to rise.

You've made that claim before. But we know that there have been huge changes in
the way concussions are diagnosed and reported, which have led to concussions
"going way up" in many sports, not just cycling. Without a more careful
analysis, we can't draw any credible conclusions about helmet effectiveness from
the increase in reported bicycle concussions.