In an independent groups design, what is the purpose of having a controlled group?

In an independent groups design, the purpose of having a control group is to provide a baseline for comparison against the experimental group. This is essential for assessing the effect of the independent variable. The control group consists of participants who do not receive the experimental treatment or manipulation, allowing researchers to observe what happens without any interventions.

By comparing outcomes between the control group and the experimental group, researchers can determine whether any observed changes in the experimental group can be attributed to the manipulation rather than other factors. This helps establish the validity of the results, ensuring that any differences in outcomes are indeed due to the treatment being tested.