Second order growth model PreviousNext
Mplus Discussion > Growth Modeling of Longitudinal Data >
 Jon Heron posted on Wednesday, July 25, 2012 - 4:33 am
Hi Bengt/Linda

I am attempting to fit second order growth models to two processes in parallel with directional associations between the various growth factors.

Say I have first order factors:- b1 b2 b3 b4 b5 b6, a1 a2 a3 a4 a5 a6
and second order factors:- aint aslope aquad bint bslope bquad

This model is stretching both me and my PC (mainly me) so I am currently contemplating a two-stage approach where I fit a simpler model that covaries all my first order factors (ai,bi). I then read the tech4 output back into Mplus and fit the parallel growth model to these vars/covs/means.

I have a feeling this approach may have some shortcomings but is still useful/valid for informing a full one-stage model -e.g. in terms of my chosen polynomials and res-variance constraints.

Does this sound reasonable or am I missing something?

cheers, Jon
 Linda K. Muthen posted on Wednesday, July 25, 2012 - 10:08 am
You can do that. Your standard errors will not be ML and may not be correct.
 Jon Heron posted on Wednesday, July 25, 2012 - 10:18 am
thanks Linda
I need to do something.
Head about to pop!

bw, Jon
 lamjas posted on Monday, January 21, 2013 - 12:36 am
Can I do a LGM on a second-order factor?

For example (as an unconditional model):

Names are
ay11-ay15 !Measured at T1
ay21-ay25 !Measured at T2
ay31-ay35 !Measured at T3

by11-by15 !Measured at T1
by21-by25 !Measured at T2
by31-by35 !Measured at T3

cy11-cy15 !Measured at T1
cy21-cy25 !Measured at T2
cy31-cy35; !Measured at T3

fa1 by ay11-ay15;
fa2 by ay21-ay25;
fa3 by ay31-ay35;

fb1 by by11-by15;
fb2 by by21-by25;
fb3 by by31-by35;

fc1 by cy11-cy15;
fc2 by cy21-cy25;
fc3 by cy31-cy35;

fabc1 by fa1 fb1 fc1;
fabc2 by fa2 fb2 fc2;
fabc3 by fa3 fb3 fc3;

s i | fabc1@0 fabc2@1 fabc3@2;
[fabc@0 fabc2@0 fabc3@0];
 Bengt O. Muthen posted on Monday, January 21, 2013 - 8:12 pm
Yes. It will be identified if you hold observed item intercepts equal across time and fix 1st-order factor intercept at zero.
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