I have a question regarding multigroup analysis with 3 groups when performing SEM. When comparing the chi-square and df between the unconstrained and constrained model, is there a way to see if there is a significant difference between each of the groups (i.e., group 1 vs. 2; group 2 vs. 3; group 1 vs. 3)? And if so where can I see it in the output? Or is it just possible to tell that there is an overall difference?
You would need to use just the data for groups 1 and 2, 1 and 3, and 3 and 3. You can do overall difference tests or test individual parameters. You can also use MODEL TEST.
ellen posted on Sunday, September 09, 2012 - 11:27 pm
Hi Dr. Muthen,
I am trying to compare parameter estimates across 3 groups. I heard that parameter differences can be tested by MODEL TEST in Mplus, but I am not sure how to write the Mplus language for MODEL TEST. Could you tell me what I should write in the input file for performing MODEL TEST to examine whether parameters are equal across groups? My model is:
GROUPING = race (1=African 2=Asian 3=Hispanic) ;
ANALYSIS: ESTIMATOR = MLR ;
Rm By R1 R2 R3 ; Ot By O1 O2 O3 ; Sg By S1 S2 S3 ; De BY D1 D2 D3 ;
Sg ON Rm ; Sg ON Ot ; Sg ON De ; Rm WITH Ot ; Rm WITH De; Ot WITH De;
MODEL African: MODEL Asian: [R1 - D3] ; MODEL Hispanic: [R1 - D3] ;
The Multigroup Chi-square difference test was significant. However, it only tells me there is overall difference; it does not tell me whether certain parameters are invariant while others are non-invariant. Rather than doing overall difference tests or constraining each parameter one at a time, how do I write the MODEL TEST language to test for specific parameter differences? (For instance, if I want to see whether the parameters of "Sg ON Rm" and "Rm with De" are equivalent across groups?)