Authors must provide enough information for readers to know how the trial was performed

Randomised controlled trials are the best way to compare the effectiveness of different interventions. Only randomised trials allow valid inferences of cause and effect. Only randomised trials have the potential directly to affect patient care—occasionally as single trials but more often as the body of evidence from several trials, whether or not combined formally by meta-analysis. It is thus entirely reasonable to require higher standards for papers reporting randomised trials than those describing other types of study.

Like all studies, randomised trials are open to bias if done badly.1 It is thus essential that randomised trials are done well and reported adequately. Readers should not have to infer what was probably done, they should be told explicitly. Proper methodology should be used and be seen to have been used. Yet reviews of published trials have consistently found major deficiencies in reporting,2 3 4 making the task …