What is the purpose of the control group in an experimental design?

The purpose of the control group in an experimental design is to provide a comparison for the intervention group. This allows researchers to isolate the effects of the independent variable being studied. By having a control group that does not receive the intervention, researchers can observe the differences in outcomes between those who do receive the intervention and those who do not. This comparison helps in determining whether any observed changes in the experimental group can be attributed to the intervention itself rather than other external factors.

For instance, if researchers are testing a new educational program, the control group would not participate in that program while the experimental group would. By comparing performance outcomes between these two groups, the efficacy of the educational program can be assessed accurately. This foundational aspect of experimental design is crucial for establishing causal relationships and enhancing the validity of research findings.