Interpreting the intercept in mixture... PreviousNext
Mplus Discussion > Latent Variable Mixture Modeling >
 fred posted on Tuesday, May 22, 2018 - 9:25 am
I am running a fairly basic multigroup analysis within the mixture model frame with known class option.

Model overall is
M by C1-C6;
M on Cohab Exp age;
DV on M Exp age ;

where both Exp and DV are binary variables (0,1)

The second group's model has the intercept of C2 freely estimated.

C1-C6 are items wit Likert-type response categories from 1 to 5.

In the output the intercept of M is repoted as:
M estimate= 0.024 SE=0.075

Here is what I am not able to understand. The scale of M is tied to the first item (C1) so it should go from 1 to 5. Also te itercept of M, I am thinking, sould be the value of M at Exp being 0 (and Cohab and centered age at 0).
I dont know how to interpret the estimated value of 0.024 (and 0.00 for the second group), especially as I want to interpret the effect of unit change in M for reporting the corresponding OR value/change in DV.

So, my question is why is the intercept of Mat around 0 when it should be somewhere between 1 to 5?

Thanks for any help!
 Bengt O. Muthen posted on Tuesday, May 22, 2018 - 5:48 pm
Mean(c1) = a + b * Mean(M), so the intercept a does not need to be the same as Mean(c1).
 fred posted on Wednesday, May 23, 2018 - 10:30 pm
Thank you, I see that about the indictor items.
My question is more about the intercept of M, since as a mediator in tis case M has intercept and not mean.

What is the faulty part in te assumption that the intercept of Mediator at b*0 (Exp at 0) should be in the scale of Mediator's items (1-5). Wouldn't Exp at 0 render the intercept of M equal to M's mean (that is M is not effected by IV and should reflect the mean of factor score)?

Thanks again
 Bengt O. Muthen posted on Thursday, May 24, 2018 - 3:46 pm
Yes, for exp=0, the mean of the factor m is the intercept of m. But that's not the mean of the factor indicators of m because the indicator equations have intercepts, so it comes back to my formula.
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