A control group is a group of participants in a clinical study that serves as a reference point for the treatment group, which receives the new intervention. The control group allows researchers to determine whether the observed effect is truly attributable to the new drug and not to other factors such as the natural course of the disease or the placebo effect.
There are different types of control groups. A placebo control group receives a sham treatment that looks exactly like the real drug but contains no active ingredient. An active control group receives an already established standard therapy. The choice of control group is an important ethical and methodological decision in study design. Without an appropriate control group, it is scientifically impossible to objectively evaluate the efficacy and safety of a new treatment. Therefore, controlled studies are the gold standard in clinical research.