The experimental group is the group in an experiment that receives the treatment or independent variable being tested. It is compared to the control group. The control group does not receive the treatment. The difference between the two groups shows the effect of the treatment. The experimental group is the one that gets the intervention.

Random assignment is essential. Participants are randomly assigned to the experimental or control group. Random assignment controls for confounding variables. It ensures the groups are similar at the start. Any difference after the treatment is due to the treatment. That is the logic of the experiment.

Experimental group characteristics

• Receives the treatment or intervention.
• Randomly assigned.
• Compared to the control group.
• Differs from control only in the treatment.
• Measures the effect of the independent variable.

The experimental group is the focus of the study. The researcher manipulates the independent variable. The experimental group gets the manipulation. The control group does not. The dependent variable is measured in both. The comparison reveals the effect. If the experimental group improves and the control group does not, the treatment worked. If both improve, the improvement might be due to something else. If neither improves, the treatment failed. The experimental group is the test. The control group is the baseline. Together they provide evidence. Without a control group, the experiment is weak. You cannot know if the treatment caused the change. The experimental group alone is not enough. The comparison is everything. That is the scientific method. Manipulate, control, compare. The experimental group is the manipulation.