The best information concerning therapeutic interventions comes from randomized controlled trials (RCTs). The validity of an RCT depends on the correct performance of a large number of essential steps. Unless all these steps are accurately accounted for and described, critical clinicians cannot know what actually took place, cannot judge whether the conclusions drawn by the authors are justified, and cannot judge whether their patients are likely to be helped or harmed by the intervention.
See also p 1015.
The object of an RCT is to produce an unbiased estimate of the effect of a therapy, a goal thwarted if allocation of patients is not random. In the February 1, 1995, issue of JAMA, we published a study of controlled trials by Schulz and colleagues.1 These authors evaluated 250 controlled trials from 33 meta-analyses and found that when the treatment allocation was inadequately concealed from study participants and investigators, when