Definition: A control group is a comparison group. To understand how effective a new medication may be, researchers need to compare it to something, often a placebo or an existing medication. The people in the control group will not be given the new medication. Generally no one knows which group they are in until the trial is finished.
Control Group for Clincal Trials
By Julie Stachowiak, Ph.D., About.com Guide
Updated: April 30, 2007
About.com Health's Disease and Condition content is reviewed by the Medical Review Board
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