Message/Author 

Jinni Su posted on Friday, September 27, 2013  1:33 pm



Hello, I want to examine a SEM model where X is hypothesized to influence Y through multiple indirect pathways that involve multiple mediators. Specifically, it is hypothesized that: X>M1>Y X>M2>Y X>M1>M3>Y X>M2>M3>Y X>M1>M2M3>Y How do I specify a model to examine all the specific indirect effects and total indirect effects of X on Y? Are the following commands correct? MODEL INDIRECT: Y IND M1 X; Y IND M2 X; Y IND M1 M3 X; Y IND M2 M3 X; Y IND M1 M2 M3 X; Y IND X; Or should I use MODEL CONSTRAINT instead? MODEL CONSTRAINT: NEW(XM1Y XM2Y XM1M3Y XM2MM3Y XM1M2M3Y); XM1Y = XM1 * M1Y; XM2Y = XM2 * M2Y; XM1M3Y = XM1 * M1M3 * M3Y; XM2M3Y = XM2 * M2M3 * M3Y; XM1M2M3Y = XM1 * M1M2 * M2M3 * M3Y; How do I obtain total indirect effects of X on Y if I use MODEL CONSTRAINT? Thanks! Jinni 


If you say MODEL INDRIECT: y IND x; you will obtain tests for all indirect effects from x to y. If this is not available, I need to know more about the scales of your variables. 

Jinni Su posted on Sunday, September 29, 2013  7:50 am



Thank you very much! I think this will work. 


I'd like to be able to do this too! But I'm new to MPlus and am wondering what to type in. I have: title: mediation; data: file = data.dat; variable: names = X M1 M2 Y; usevar = X M1 M2 Y; missing = all(999); analysis: type = general; bootstrap = 5000; output: cinterval (bcbootstrap); model: Y on M1 M2 X; M1 on X; M2 on X; MI with M2; model indirect: Y ind X 


This looks correct. Give it a try. 


I don't seem to get XM1M2Y in the output, just the two specific indirect effects separately. Am I looking in the wrong place in the output? I'm quite new to this. 


You need m2 ON m1; you have m1 WITH m2; 


Ah, thanks Prof.! I suppose if I want to add an M3 into the chain, then I would need: model: Y on M1 M2 M3 X; M1 on X; M2 on X; M3 on X; M3 on M2; M2 on M1; Is that right? 


You use an ON statement for whichever regression you want. 

Back to top 