An experimental group is the group in a designed experiment that receives the treatment or condition that the researchers are testing. It’s the group that is exposed to the independent variable, which allows researchers to observe any changes or effects that result. The outcomes in the experimental group are typically compared to those in a control group, which does not receive the treatment.
The purpose of having an experimental group is to determine whether the treatment causes a measurable difference. By isolating one factor and observing its impact, researchers can test cause-and-effect relationships. This design is common in laboratory experiments, clinical trials, psychology studies, and other research fields where variables can be manipulated.
For example, in a clinical trial testing a new medication, the experimental group would be the participants who receive the actual drug. Researchers would compare their outcomes—such as changes in symptoms or side effects—to those of participants in the control group, who might receive a placebo. Any consistent differences between the groups help determine whether the medication is effective.