I have a latent construct that is measured by 3 indicators.

Let's look at the case with three periods:

- I specify covariances between the error variance from the indicators across each period over time, but only from the same indicator --> 9 covariances

- I specify covariance between the latent constructs --> 3 covariances

- I fix the mean of all the constructs to 0 and the variance to 1

This leads to a model with 54 distinct sample moments and 39 distinct parameters to be estimated, meaning 15 degrees of freedom.

Still, AMOS tells me, that the model is not identified and needs one additional constraint. I am not even sure that I should specify mean and variance for each period, I believe fixing it in one period should suffice...

Any help is greatly appreciated.