Which of the following is not a condition for establishing a causal relationship?

In the context of establishing a causal relationship, it is essential to recognize that causation implies a specific directional influence where one variable, often referred to as X, affects another variable, Y. A condition for a causal relationship is that X must precede Y, ensuring that the cause comes before the effect. Additionally, it is critical that any potential alternative explanations for Y are ruled out, confirming that X is indeed the cause.

The requirement that X and Y must consistently covary means that changes in X should correspond to changes in Y for a true causal relationship to be observed. This consistency in the relationship strengthens the claim that X influences Y.

However, stating that Y must always be a dependent variable is not accurate within the context of establishing causation. While Y is often treated as a dependent variable in research settings focused on causal relationships, it is not a strict requirement in the theoretical framework of causality. Variables can interchange roles, and the classification depends on the research design rather than a foundational principle of causation. Therefore, the idea that Y must strictly be a dependent variable does not hold as a necessary condition for establishing a causal relationship.