Research Analysis of Mediation and Moderation

The study by Nima et al (2013) explored the mediating and moderating effect of anxiety, stress, negative effect and positive effect on depression. Hence, the author used both the mediating and moderating variable in the multiple regression. Mediation was used to assess the effect of stress and anxiety as mediator variables on the relationship between self-esteem, effect and depression. Similarly, the author wanted to test the moderation effect between anxiety, stress, self-esteem and impact on depression. However, most of the analysis was inclined on mediation. Mediation was the most appropriate choice since it showed the effect of stress and anxiety, respectively, on the relationship between self-esteem and effect on depression. Nima et al. asserts that mediation assess whether the mediating variable account for a significant amount of shared variance between the explanatory and response variable. Hence, mediation was suitable in the study in assessing the effect of mediators, stress and anxiety, on the predictor variable and response variables. Moderation only assess the effect of interaction between variables on the response variable. The approach requires standardization of variables to avoid multicollinearity and may fail to give accurate results. Although the authors tested moderation effect, it had no significant impact on the result in my view. The authors displayed the results in form of tables and figures which explicitly showed the effect of mediation and moderation. The table for mediator could be interpreted alone since it had shown the two steps which shows the significance of predictor variables on response variable and there effect when stress was applied. Besides, the moderation effect figure could be interpreted alone since the interactions are visible indicating the effects.

Table 1

Figure 1: Showing the significant interaction between stress and negative affect upon depression

Figure 2: Showing the significant interaction between positive and negative affect on depression

Reference

Nima, A. A., Rosenberg, P., Archer, T., & Garcia, D. (2013). Anxiety, Affect, Self-Esteem, and Stress: Mediation and Moderation Effects on Depression. PLoS ONE, 8(9), e73265. https://doi.org/10.1371/journal.pone.0073265