randomised controlled trial
randomised controlled trialA trial in which participants are assigned by chance to receive either an experimental or control treatment. When randomisation is done properly, the effect of a treatment(s) can be studied in groups of people who are:
(1) the same at the outset, and
(2) treated the same way, except for the intervention(s) being studied. Any differences seen in the groups at the end can be attributed to the difference in treatment alone, and not to bias or chance.