What is the purpose of a control group in an experiment?

The purpose of a control group in an experiment is to serve as a baseline for comparison against the experimental group. This group does not receive the treatment or intervention that is being tested, which allows researchers to observe how the experimental group reacts to the treatment in comparison to the control group. By having this comparative aspect, researchers can determine whether the changes observed in the experimental group are due to the treatment or if they might have occurred regardless of the treatment, thereby enhancing the validity of the results. The control group helps isolate the effect of the independent variable by providing a standard against which changes can be measured.

Maintaining a control group is crucial for establishing a cause-and-effect relationship in experimental research. The absence of a control group would make it difficult to draw any firm conclusions about the efficacy of the experimental treatment. The comparison not only helps in confirming the results but also in identifying any potential confounding variables that could affect the outcome.