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Randomized Controlled Trial- Definition of Randomized Controlled Trial


Updated March 20, 2009


Considered the gold standard to test a treatment for a disease such as asthma. Patients are assigned to either a treatment or a placebo, or sugar pill. By comparing the outcomes (such as the number of ER visits or improvement in pulmonary function in asthma), investigators can determine if treatment is useful.

Many patients are concerned about being on a placebo treatment, which prevents them from participating in clinical trials. It is important to realize that as a participant, you have the right to withdraw at any time. Additionally, with "human subjects protection," investigators must give patients at least the minimum current standard of care with an investigational drug on top of the usual. For example, it is unlikely that an asthma study would be approved that did not conform to current asthma guidelines for asthma treatment.

During the informed consent process, the investigator should explain all the information about the study drug, use of a placebo, and possible side effects.


U.S. National Institutes of Health. Consumer Information. Accessed March 15, 2009. Understanding Clinical Trials.

Ducharme FM, Lemire C, Noya FJ, Davis GM, Alos N, Leblond H, Savdie C, Collet JP, Khomenko L, Rivard G, Platt RW. Preemptive use of high-dose fluticasone for virus-induced wheezing in young children. N Engl J Med. 2009 Jan 22;360(4):339-53.

Also Known As: RCT
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