One of the potentially most useful features of the Cochrane Library is the “Add/View Feedback” link positioned (alas, not very conspicuously) towards the bottom of the menu that appears each time a review (or a protocol for a review) is selected. Users of the Library can leave their own comments or criticisms and see what others might have said. It is possible, for example, to query the approach that reviewers have described in their protocol or to draw attention to new trials published since a review was last updated. Like other Cochrane review groups, however, we find that this facility is seldom used.

It is interesting when a review bucks the trend and attracts copious feedback. The Cochrane Injuries Group review that has been most successful in prompting readers to post their comments is “Helmets for preventing head and facial injuries in bicyclists”,¹ which concluded, “Helmets reduce bicycle-related head and facial injuries for bicyclists of all ages involved in all types of crashes, including those involving motor vehicles”. The explanation for the interest in this review seems to be that anti-helmet passions are currently running high, as has often been the case with road safety interventions—for example, seatbelts.

Some of the comments posted on the helmet review are longer than the review itself. It is unfortunate that the same points have been made (often by the same people) over and over again, and that most of the criticism has very little to do with the review itself, involving instead discussion of theoretical issues relating to helmet use. Indeed, the critics have argued that only when the theory for an intervention is good should a systematic review be carried out of its use in practice. This is very far from the view taken within the Cochrane Collaboration; if an intervention is in widespread use (and many of us wear cycle helmets) there is a pressing need to evaluate its real world effectiveness. If reviewers had waited till the theory looked good, then many of the drugs in common use would never have been the subject of a systematic review!

The helmet review’s critics have also made, and repeated, incorrect statements about individual studies included in the review. So, all in all, this is not an instance of the comments facility being used effectively. Nevertheless, we do hope to get more feedback on our work, including another review and a protocol that also deal with bicycle helmets.^2,3

This will be the last time that this column is written by me. I am moving to become an Editor with PloS Medicine, the new open access general medical journal from the Public Library of Science (http://www.plos.org). However, I shall retain my interest in injury prevention, which is a field that we need to see covered more fully and more often in the general medical literature.