What role does a control group play in evaluation research?

In evaluation research, a control group is crucial because it serves as a baseline against which the effects of the intervention can be measured. By not receiving the intervention, the control group helps to isolate the specific impact of the program being evaluated. This comparison allows researchers to determine whether observed changes in the experimental group, which does receive the intervention, are truly due to the intervention itself or if they might be attributed to other external factors or naturally occurring variations over time.

The presence of a control group enhances the validity of the study's findings. It helps mitigate potential biases and confounding variables, enabling researchers to draw more reliable conclusions about the effectiveness of the intervention. Ultimately, the control group enables a clearer understanding of the causal relationship between the intervention and any outcomes observed.