What is a “control group” in the context of experimental evaluation?

A control group is a fundamental element in experimental evaluation, serving as a baseline to compare against the group that receives the intervention being studied. It does not receive the treatment or intervention, allowing researchers to isolate the effects of the intervention from other variables. This comparison is critical in determining whether observed changes in the experimental group can be attributed to the intervention itself rather than external factors.

By having a control group, researchers can better ascertain the causality of the intervention's effects, ensuring that any positive outcomes in the experimental group are indeed a result of the treatment. This method enhances the validity and reliability of research findings, making it easier to draw conclusions about the effectiveness of the intervention being evaluated.