NCIt definition : Assignment of subjects by chance to groups that receive different treatments.;
Alternative definition : NCI-GLOSS: 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.;