

Adding/Subtracting Two Latent Factors 

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Hello, VIA CFA with ordinal indicators and the WLSMV estimator, I've obtained two latent variables of concepts that are of interest to me, say X and Y. Fit of the model is excellent, and I'd like to move on to full SEM where I test the followingA large gap between the respondent's location on factor X and their location on Factor Y drives evaluations of Z. I have read up on the warnings associated with using saved factor scores in a separate analysis, so is there a way to combine factors in an additive or subtractive manner? Thanks, Tom 


Would it work to consider Z = a + b *(XY ) + e and say Model: Z ON X (posb) Y (negb); Model Constraint: 0 = posb+negb; 


Hi, Sorry to be delayed before coming back to this. I'm not really clear on the logic here? As an output with the constraint, I receive Z on X 1.044 Y 1.044 I need the direct effects of X and Y and the interactive effects Perhaps an easier way would be to create another latent variable that somehow is the difference between the two and then use all three in the path model. Can this be done? I thought one way might be to try to do something similar to latent change modelling and introduce a phantom difference factor, but I'm not sure I'm on solid ground. Best, Tom 


Hi, After writing, I realised my language was unclear. What I mean to say is I need the effects of the difference between x and y on z. I do NOT want to interact the two factors. Tom 


You can do what you suggest. 

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