I ride without a helmet the same speed I drive without a seatbelt.

Unsurprising how some studies get confirmed here by anecdotes.
But some other studies? Garbage, I tell you, garbage! Utter rubbish! Magic hats!

Another (significantly more reliable) way to find out the quality of a study? Look at the cites of the study. (I know, I know, using scholar.google.com is so hard.)
Most of the papers cited by the anti-helmet crowd don't stand up very well. (I'm understating the science here.)

This paper is a survey of SOME of the MANY follow up studies published on many of the studies commonly cited here.

For example, Walker, I (Drivers overtaking bicyclists) does not hold up well at all. As in, not at all.
(Apropos nothing at all, some of the same people who object to a "small sample size" of 1,000 glowingly cite a study with a sample size of ONE.)

The "risk compensation" papers now being discussed here don't hold up very well either.

-mr. bill