Risk compensation theory should be subject to systematic reviews of the scientific evidence.

Background Many readers of Injury Prevention are quite familiar with the debate over bicycle helmet use. The core of this debate is the opinion on one side that helmets are eVective and thus should be worn, countered on the other side by the belief that risk compensation negates this protective eVect of helmets. A systematic review on helmet eVectiveness has been published in the Cochrane Library. The objective of the Cochrane review was to determine whether bicycle helmets reduce head, brain, and facial injury for bicyclists of all ages involved in a crash. The principles required of high quality evidence based reviews were followed: a comprehensive literature search, pre-established study selection criteria, and most importantly a critical review of study methods. A well conducted systematic review identifies and considers all the literature (peer reviewed, government reports, and unpublished papers), and rates the study quality. Appropriately, such reviews only include better designed and conducted studies. The evidence is then summarized across all the studies. The literature search for the Cochrane review yielded five studies meeting the preestablished criteria for inclusion. The strengths and weaknesses of five case-control studies of bicycle helmet eVectiveness were carefully evaluated. The scientific evidence which indicates that bicycle helmets protect against head, brain, severe brain and facial (upper and midface) injuries has been well established. Additionally, the evidence indicates that helmets provide injury protection in all type of crashes including those involving motor vehicles. Based on this review the authors recommended that as a policy bicycle riders of all ages should be encouraged to wear helmets. The purpose of publishing health research, and discourse about it, is to improve the health of the public. We believe that the evidence indicates such a strong protective eVective of helmets, that the net eVect on the health of the public will be positive.