In medical studies, a treatment, medicine, or therapy given to study participants that is known to have no therapeutic effect on the condition of interest. Placebos are used in clinical trials because they help control an important variable: whether or not the participants know that they are receiving treatment for a condition. With a placebo, neither the participants receiving an experimental treatment and nor those in the control group know whether they are receiving the treatment. To learn more, visit our side trip Fair tests in the field of medicine.
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