

Total Vs. Indirect Effects 

Message/Author 


Hello I have been running some models with two mediating variables (both latents) and have come across some somewhat strange findings I am not sure how to interpret. In a nutshell, we are finding that the total indirect effect is significant, but the specific indirect effects are either marginally significant or not significant. For example, we are predicting child PTSD symptoms from parental IPV, looking at both parenting and psychopathology as mediators. In the model, we correlate parenting and psychopathology, and examine both mediators simultaneously. The total indirect effect is significant, parenting is only marginally significant (p=.07), and psychopathology is not. The correlation between parenting and psychopathology is .27 when we use IPV perpetration in the model, and .39 when we use IPV victimization in the model. So how can we interpret this? Do we just say it is clear that both parenting and psychopathology exert an influence on child PTSD symptoms, but we can't specify how each independently effects child PTSD symptoms? Does that also mean that because parenting and psychopathology are moderately correlated that we can't really "tease" apart their independent influence? Thanks! heather 


My answer to the last two questions is yes. 


Hi Linda  I'm making some mistake I can't figure out in using the MODEL INDIRECT command. Here is my model: MODEL: ! all vars latent, MLR outcome ON coping dist_3d readmitb ; dist_3d ON coping ; MODEL INDIRECT: outcome IND dist_3d coping ; Output says, "TOTAL, TOTAL INDIRECT, SPECIFIC INDIRECT, AND DIRECT EFFECTS", but I'm only getting the specific indirect effect in the output, and I'd like the total effect also. What am I not specifying correctly? Thanks! bac 


You need to specify outcome IND coping ; to get total effects. 

db40 posted on Sunday, August 10, 2014  12:07 pm



Hi, How do I interpret output where there is a sig effect from x to y, m to y, and x to m however the total effect is non sig whilst the indirect and direct effects are sig? Does this refer to inconsistent mediation and does this mean that it is partially mediated? 


Please ask these questions on a general discussion forum such as SEMNET since they are not specific to Mplus features. 


Dear Dr. Muthen, For my PhD research, I am running a model to test a mediation effect. My outcome variable is categorical, and for running my model, I used the WLSMV estimator with 1000 bootstraps to assess for mediation. However, I obtained a result in which the total effect is not significant, the direct effect is not significant either, and the indirect effect is significant. The results that I obtained for the total effect was this: Estimate SE Est/SE pvalue 0.721 0.739 0.976 0.329 However, the direct effect and the indirect effect have the same sign, which means that we don't have here an inconsistent mediation or suppression effect. Therefore, do you think that we can still say that we have a mediation effect, even when the total effect is not significant, but when the direct effect and the indirect effect have the same sign, which results in a total effect higher than the direct effect? Do you think that the fact that the total effect is not significant could be due to the fact that the SE is higher than the estimate? Many thanks in advance for your help, 

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