Measurement invariance across both gr...
Message/Author
 Stefan Kulakow posted on Saturday, April 01, 2017 - 2:59 am
Dear Mr. and Mrs. Muthen,

I'm doing a longitudinal study and try to test for measurement invariance. For this, I took Little's (2013) approach and added the constraints simultaneously to both groups and measurement times.

Consequently, for strict factorial invariance I constrained the intercepts of all observed variables, but there I faced the problem, that I could not estimate the latent factor means. For group 1, the estimates for both time points are constrained to 0; I could only estimate the latent mean differences for group 2. However, this model seems too restrictive since it doesn't allow the mean at time 2 for group 1 to vary.

Is there any way to solve this.

Thank you very much in advance.
 Stefan Kulakow posted on Saturday, April 01, 2017 - 3:17 am
My mistake - meant "strong factorial invariance"
 Bengt O. Muthen posted on Saturday, April 01, 2017 - 4:41 pm
With 2 groups and 2 time points you fix the factor mean to zero in only 1 of the 4 cases, e.g. for the control group at time 1.
 Stefan Kulakow posted on Sunday, April 02, 2017 - 4:18 am
I tried to do that, however I haven't managed to estimate the factor mean at time2 for group 1.

model:

TIME1 by
t1
t2 (1)
t3 (2)
t4 (3)
t5 (4);

TIME2 by
t1_2
t2_2 (1)
t3_2 (2)
t4_2 (3)
t5_2 (4);

[t1@0 t1_2@0];
[t2 t2_2] (int1);
[t3 t3_2] (int2);
[t4 t4_2] (int3);
[t5 t5_2] (int4);

[TIME1@0];
[TIME2*];

model control:

[TIME1*];
[TIME2*];
 Linda K. Muthen posted on Sunday, April 02, 2017 - 6:37 am