Well, if you want to read the actual study (it wasn't done at the time), here it is --

http://www.bikeforums.net/attachment.ph … 1262472722

I particularly like this part --

   Although our data set did not find significance in relative risk of cycling without helmet
   (most likely due to small sample size), it did show a trend consistent with previous studies
   that form an over-whelming body of evidence that helmets prevent injuries and save lives,
   and laws should be passed to encourage cyclists to wear helmets.

... so, upon looking more closely at the data, he found that it didn't actually say that helmets
prevent injuries (even though the initial press releases said that the data very strongly
suggested that), but he still he somehow found encouragement to keep pushing for helmet laws.