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

The purpose of a control group in an experiment is to provide a baseline for comparison with the treatment group. By having a control group that does not receive the experimental treatment or intervention, researchers can observe what happens in the absence of the treatment. This allows them to determine whether any observed effects in the treatment group are due to the treatment itself or other external factors. Without a control group, it would be challenging to draw valid conclusions about the efficacy or impact of the treatment, as there would be no point of reference to measure changes against.

In well-structured experiments, the control group maintains all other conditions constant that might influence the results, helping to isolate the effect of the treatment being tested. This comparison is critical for validating the findings and ensuring that the outcomes attributed to the treatment are meaningful and significant.