Which term refers to the condition that the observed association between two variables is not due to extraneous variables?

• A. Association
• B. Direction of influence
• C. Non-spuriousness
• D. Random assignment

Answer: (C)

Non-spuriousness is about making sure the link you see between two variables isn’t explained by a third factor. In research, an association can look real but actually be caused by something else that influences both variables. To claim non-spuriousness, you show that once you account for those extraneous variables—through experimental design like random assignment or through statistical controls in observational studies—the association still exists and isn’t explained away by the third variable. For example, if higher income and better health are linked, you’d check whether education level or age accounts for that link. If, after controlling for those factors, the relationship remains, it’s non-spurious. If it disappears, the initial association was spurious. The other concepts involve the existence of a relationship (association), whether one variable causes the other (direction of influence), or a method to reduce confounding (random assignment), but they do not define the idea that the observed link is free from the influence of extraneous variables.