a clinical experiment in which neither the patients nor the researchers are aware of which patients are receiving the active treatment and which are receiving placebo
Participants in this type of trial are divided into two or more groups: one gets the experimental treatment; the other gets the standard treatment or a placebo. Neither the researchers nor the participants know who is taking which drug until the trial is over.
A clinical trial considered the gold standard for testing effectiveness of drugs and medicine. Neither the researcher nor the subjects taking part in the trial know whether the drug being given in any individual case is the active drug or a placebo. This kind of trial aims to make the research free from bias.