A study in which the participants are assigned by chance to separate groups that compare different treatments; neither the researchers nor the participants can choose which group. Using chance to assign people to groups means that the groups will be similar and that the treatments they receive can be compared objectively. At the time of the trial, it is not known which treatment is best. It is the patient’s choice to be in a randomized trial.
In epidemiology, a clinical trial in which subjects have been randomly assigned to various groups in the study.
In a randomized clinical trial, each participant is assigned by chance (through a computer or a table of random numbers) to one of two groups. The investigational group receives the therapy, also called the active treatment. The control group receives either the standard treatment, if there is one, for their disease or condition, or a placebo.