Tengiat Loi posted on Tuesday, September 18, 2018 - 5:49 pm
Dear Prof. Muthen,
I have wrote a Mplus syntax for a 1-1-1 multilevel model in which a path is moderated by w and b path is moderated by z. I am concerned about whether cab is considered covariance or residual covariance. If that's is residual covariance, how should we compute it in model constraint and model it in the mediation?
WITHIN = x ; between = w z; CLUSTER = id; ANALYSIS: TYPE = twolevel random; ESTIMATOR = mlr; MODEL: %WITHIN% sc | y ON x; sa | m ON x; sb | y ON m; %BETWEEN% sa sb sc m y w z ; m on w; y on z; sa on w(a2); sb on z (b2); sa with sb (cab); sa with sc m y; sb with sc m y; sc with m y; m with y; [sa](a1); [sb](b1); [w](wmean); [z](zmean);
MODEL CONSTRAINT: NEW(saMean sbMean Windlow Windhigh Zindlow Zindhigh);
Why don't you grandmean center w and z so that their means are zero. The cab parameter is the residual variance but that is the relevant variance because you are considering effects conditional on w and z.
Tengiat Loi posted on Wednesday, September 19, 2018 - 7:03 pm
Thank you very much Bengt!
Tengiat Loi posted on Tuesday, April 09, 2019 - 1:45 pm
Should I group mean center m and y before transferring the data to mplus file?
I ask because the centering function
define: center m and y(groupmean)
is not allowed once they are specified at between level.