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 Marie Alice posted on Tuesday, September 06, 2016 - 7:51 pm
I am running a multi-group mediation analysis (Y=math achievement, X=single parent, M=parental involvement, Group=urban). (1) Through comparison of various equality constraints, when I find that: direct effects of Y on X, and Y on M differ across groups, but direct effect of M on X do not differ significantly across groups, should I conclude that indirect effects do not differ significantly across groups?
(2) How can I test the above indirect effect in multi-group analyses?
Currently, my syntax is as below, where I set equality constraints (A) on the direct effect one by one.

grouping=urban
analysis:
type=missing;
iterations=50000;
model:
math on single pinvolv female sibling peduc;
pinvolv on single (A);
pinvolv on peduc;
single on peduc;
(where female, sibling, peduc are control variables)
 Bengt O. Muthen posted on Wednesday, September 07, 2016 - 5:53 pm
To test equality of indirect effects across groups you create the indirect effects in Model Constraint as

ind1 = a1*b1;
ind2 = a2*b2:

diff = ind1-ind2;

where ind1, ind2, and diff are NEW parameters and the a's and b's are labels given to the parameters in the MODEL command. A z-test is then produced for diff1 being different from zero.
 Marie Alice posted on Wednesday, September 07, 2016 - 9:02 pm
Thank you for your quick response.
I was able to run the above to test whether the indirect effects differed significantly. Thanks much.
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