Which is a disadvantage of an independent groups design?

An independent groups design involves different participants being assigned to each condition of the experiment. While this method has many advantages, one significant disadvantage is that perfect control over all extraneous variables is often difficult to achieve, especially in real-world settings.

In independent groups designs, although random assignment helps to mitigate the effects of confounding variables, the variability among different groups can still lead to differences in outcomes that are not due to the independent variable being tested. This lack of control can introduce noise into the results, making it harder to establish clear cause-and-effect relationships. Thus, the complexity and unpredictability of real-life contexts present challenges that can impact the validity of conclusions drawn from the study.

This understanding illustrates why considering environmental factors and participant differences is crucial when interpreting the results of experiments using this design.