Mediators play what role in relation to independent and dependent variables?

Mediators are critical components in understanding the process through which an independent variable (IV) affects a dependent variable (DV). By definition, a mediator acts as an intermediary mechanism that elucidates the relationship between the IV and the DV. Specifically, the presence of a mediator allows researchers to unpack the causal pathway; it explains the "how" or the mechanism by which the IV influences the DV.

For instance, if the IV is a specific intervention and the DV is an outcome measure, the mediator may represent changes in attitudes or behaviors that occur as a result of the intervention. Thus, it provides insight into the processes at play, showing that while the IV has an impact on the mediator, the mediator, in turn, influences the DV.

This concept is a foundational aspect of mediation analysis in research, emphasizing the importance of understanding the sequence of effects rather than merely establishing a direct link between the IV and DV.