What role do control groups play in research?

• A. They help document behavior in a natural setting
• B. They allow for assessment of external validity
• C. They determine if the independent variable affects the dependent variable
• D. They improve sampling bias

Answer: (C)

Control groups are essential in research because they provide a baseline against which the effects of the independent variable can be measured. In an experiment, the control group does not receive the treatment or manipulation applied to the experimental group. By comparing outcomes between the control group and the experimental group, researchers can determine if any observed changes in the dependent variable are indeed due to the manipulation of the independent variable, rather than other extraneous factors. This causal relationship is vital for establishing the validity of the research findings, ensuring that any conclusions drawn about the effects of the independent variable are well-supported.

While documenting behavior in a natural setting, assessing external validity, and improving sampling bias are important aspects of research design, they do not directly relate to the primary purpose of a control group, which focuses specifically on establishing cause-and-effect relationships.