The QUORUM statement (Nov 27, p 1896)¹ should prove useful to people writing and intepreting reports of systematic reviews. The promised update should include a recommendation that authors of a systematic review clearly indicate whether any other versions of the review have been published and the status of these versions, to show which is the most up-to-date. Reviewers have struggled for some time with difficulties caused by multiple publication of randomised trials without appropriate cross referencing.