The degree to which a quasi-experiment supports a causal claim depends on which of the following?

• A. The number of participants in the study
• B. The use of random assignment to conditions
• C. The extent to which confounding variables are controlled
• D. The length of time the study is conducted

Answer: (C)

Verified step by step guidance

1. Understand that a quasi-experiment differs from a true experiment mainly because it lacks random assignment to conditions, which affects the ability to make strong causal claims.
2. Recognize that controlling confounding variables is crucial in any experimental design because these variables can provide alternative explanations for the observed effects, thus weakening causal inferences.
3. Evaluate why the number of participants, while important for statistical power, does not directly determine the strength of causal claims in quasi-experiments.
4. Consider that the length of time a study is conducted may influence other factors like reliability or longitudinal effects but does not inherently strengthen causal claims without control of confounds.
5. Conclude that the key factor for supporting causal claims in quasi-experiments is how well confounding variables are controlled, as this reduces alternative explanations and increases internal validity.