

Multigroup analysis with 3 groups 

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Dear all, I have a question regarding multigroup analysis with 3 groups when performing SEM. When comparing the chisquare 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? Thank you so much for your answer in advance. CarmenMaria 


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 ; MODEL: 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; [Rm@0 Ot@0 Sg@0 De@0] ; MODEL African: MODEL Asian: [R1  D3] ; MODEL Hispanic: [R1  D3] ; The Multigroup Chisquare 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 noninvariant. 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?) 


You need to label the parameters you want to test. See the user's guide under MODEL CONSTRAINT to see how labeling is done. See MODEL TEST for an example of how to test using the labels. 


Hi Dr. Muthen, On Wednesday, June 27, 2012  11:37 am, you wrote: 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. Di you mean "and 2 and 3" instead of "3 and 3"? Thank you! 


Yes. 

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