What is the purpose of a control group?

The purpose of a control group in research is to serve as a baseline for comparison against the experimental group that receives the treatment. By not receiving the intervention, the control group helps researchers observe what may occur naturally without the influence of the treatment being tested. This comparison allows researchers to isolate the effects of the treatment, thereby demonstrating the impact of the intervention itself. Essentially, the control group provides a clearer understanding of the treatment's effectiveness, revealing any differences in outcomes attributable to the treatment rather than other external factors. This is crucial in establishing causal relationships and ensuring the validity of the study's findings.