Assignment task:
Mediation and Moderation in Social Research
Moderator variables establish the domain of maximal effectiveness of an independent variable (IV) by separating the sample into subgroups where the effect of the IV on the dependent variable (DV) differs in strength or direction. They address when or for whom an effect occurs. Statistically, a moderator is represented by an interaction effect between the IV and the moderator variable on the DV. In contrast, a mediator variable (M) represents the generative mechanism or process through which the IV can influence the DV. Mediators address the how or why an effect occurs by proposing a causal chain: the IV causes the mediator, and the mediator then causes the DV. This difference is crucial, as mislabeling these variables can lead to defective theoretical conclusions and inappropriate statistical analyses. Baron and Kenny (1986) formalized this crucial distinction and provided the initial causal steps framework for statistically testing mediation hypotheses with regression. Distinguishing between them is essential because the concepts represent fundamentally different causal models: moderation is about conditions, while mediation is about process. The choice between a moderator model and a mediator model reflects two distinct hypotheses about how a conceptual variable accounts for behavioral differences. A comprehensive understanding of the statistical models and assumptions is foundational to conducting a valid mediation analysis (MacKinnon, 2008).
Application of a Mediator Model
The Journal of Veteran Studies article titled, Does attachment mediate PTSD and suicidality in a sample of Global War on Terrorism (GWOT) combat veterans? (Carbajal & Ponder, 2022), investigates the psychological process linking trauma-related disorders to severe outcomes in veterans. The study conducted parallel mediation models to test the reciprocal relationship between posttraumatic stress disorder (PTSD) and suicidality. A key model tested suicidality as the Independent Variable (IV) and PTSD symptoms (PCL-5) as the Dependent Variable (DV), with generalized anxiety, depression, and attachment avoidance/anxiety serving as the Mediators (M). Specifically, the results indicated that the relationship between suicidality and PTSD was significantly mediated through Depression, demonstrating that the relationship between suicidality is related to PTSD symptoms due to the intervening of depression. This finding emphasizes the importance of targeting depression in clinical interventions for this population, which is the practical benefit of identifying mediational pathways (Carbajal & Ponder, 2022). Need Assignment Help?
References:
Baron, R. M., & Kenny, D. A. (1986). The moderator-mediator variable distinction in social psychological research:
Conceptual, strategic, and statistical considerations. Journal of Personality and Social Psychology, 51(6), 1173-1182.
Carbajal, J., & Ponder, W. N. (2022). Does attachment mediate PTSD and suicidality in a sample of Global War on Terrorism (GWOT) combat veterans?. Journal of Veterans Studies, 8(1), 208-221.
MacKinnon, D. P. (2008). Introduction to statistical mediation analysis. Lawrence Erlbaum Associates.
Does Attachment Mediate PTSD and Suicidality in a Sample of Global War on Terrorism (GWOT) Combat Veterans?