

Can a grouping variable change over t... 

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Hai, I am testing a multilevel structural equation model with a 3wave longitudinal dataset. I have nested all three measurements within individuals and all the paths I am interested in include withinlevel variables. I would now like to perform group analysis to my data. So I would like to see if the coefficients are different between group 1 and group 2 of the sample. The problem is that the grouping variable is also a withinlevel variable and is changing over time. So its value can be either 1 or 2 across times 13. How can I do that with Mplus? Thank you in advance. Kind regards, Paris Petrou 


You should use the grouping variable as a dummy timevarying covariate. 


Thank you very much Linda. The reason why I need to do that is because I am using an incogruence score between A and B (both withinlevel variables) as a predictor in my model. I am more interested in the incogruence than the interaction between the two variables. But in order to address criticisms around the use of incogruence scores, I would need to perform my analyses for two groups: Group 1: A > B and Group 2: A < B. If I use the grouping variable as a dummy timevarying covariate, I will control for its effect, but I will still not be able to compare the results between group 1 and group 2. The only way to do that is to create an interaction between my incogruence score and the covariate? But this is too complicated and I am not sure what that variable would mean. Then it would be better to use an interaction term all the way from the start, right? Best, Paris 


I don't understand this type of data setting well enough to answer. You may want to ask the question on SEMNET. 


OK, thank you. 

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