Merits and limitations

The merits and limitations of randomised controlled trials in general have been widely discussed 5 6; only key points are repeated here. In clinical medicine, the randomised controlled trial is considered the best way of measuring the efficacy of interventions because of its ability to minimise bias and avoid false conclusions. Random assignment of individuals to different treatment groups is the best way of achieving a balance between groups for the known and unknown factors that influence outcome. This may seem to run counter to the traditional medical model of the doctor deciding which treatment is best for each patient, but it is considered ethical only when there is genuine uncertainty about which treatment to offer. By the same token, failure to tackle genuine uncertainty about treatments through randomised controlled trials can be considered unethical because it allows ineffective or harmful treatments to continue unchecked.