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

The role of a control group in an experiment is to serve as a baseline to compare the effects of the experimental variable. By having a control group that does not receive the treatment or intervention being tested, researchers are able to isolate the effects of the experimental variable. This comparison allows for a clearer understanding of whether any changes in the experimental group are truly due to the variable being tested, rather than other confounding factors. The control group remains unchanged and provides a standard against which the results can be measured, ensuring that the conclusions drawn from the experiment are valid and reliable.