When exploring causal relationships, which of the following statements is true?

The statement that one variable must precede another in time is a fundamental aspect of establishing causal relationships. In research, for a causal link to be identified, the cause (independent variable) must occur before the effect (dependent variable). This temporal precedence helps differentiate causation from mere correlation, ensuring that any observed changes in the dependent variable can be attributed to the manipulation of the independent variable rather than occurring randomly or due to other factors. This is crucial in research design, especially in fields like social work, where understanding the timing of interventions can significantly influence outcomes.

The other statements do not accurately reflect the necessary conditions for establishing causal relationships. For example, asserting that both variables must remain independent contradicts the requirement for a cause-and-effect dynamic, as causation inherently involves a dependent relationship between the variables. Additionally, stating that all variables must be qualitative unnecessarily limits the types of variables that can be analyzed; both qualitative and quantitative variables can be involved in causal research, depending on the context. Lastly, relying solely on correlational data does not suffice for determining causality, as correlation alone does not imply that one variable causes changes in another; it merely indicates that a relationship exists, without establishing the direction of influence or accounting for potential confounding variables.