Niki Su posted on Thursday, February 01, 2018 - 11:42 pm
I want to run a 1-1-1 MSEM with one slope fixed and I don't know how to write the script to estimate the indirect effect. Here is my script:
%within% m on x(aw); sb|y on m; sc|y on x;
m on x(ab); y on m(bb); y on x; [sb](bw);
Niki Su posted on Friday, February 02, 2018 - 2:01 am
One more question, in my experiment. x is a within-subject variable with 2 levels. Thus x has no between-group variation. Can I estimate the indirecr effect through a model in which x is't claimed as "Within are"?
Niki Su posted on Friday, February 02, 2018 - 5:38 am
Following the last question, since x only has within-group variation, the mediation effect must occur strictly at the within-group level, and there must be no Between indirect effect though both m and y have between-group and within-group variation. Then the script of the 1-1-1 MSEM can be the following:
within=x; analysis:type is twolevel random;
%within% m on x(aw); !The slope is fixed because the correlation of random slope and intercept is 1.
sb|y on m; sc|y on x;
%between% !m on x(ab); The path is commented out because x only has within-group variation.
y on m(bb);
!y on x; The path is commented out because x only has within-group variation.
model constraint: new(indw); indw=aw*bw;
Please tell me whether I am right. Thank you very much.