What are “blind” or “masked” studies?
Many clinical trials have two groups of volunteers: a group that will be given an experimental drug or receive an experimental treatment, or a group that is “controlled” meaning that the doctors have control of what the group receives. The controlled volunteers receive either a standard treatment for the illness, a placebo, or no treatment at all. Because you are not sure which group you are in until the end of the study, the study is sometimes referred to as “blind” or “masked”. Sometimes, clinical trials are “double-blind” or “double-masked.” That means that neither the participants, nor the study staff members know who is receiving the experimental treatment and who is in the control group receiving either a standard treatment or a placebo. Studies are performed in this way so that neither the patients’ nor the doctors’ expectations about the experimental drug can influence the results.
