Thanks in advance for any insight people have to offer! I am in the very early stages of fitting a four time point model where the data exhibit non-linearity. I specified a freed loading growth model where time point 1 is fixed at 0, time point 2 is fixed at 1 and time points 3 and 4 are free, and am fitting the model separately for boys and girls.
The model in which I simply fit the growth curves ran fine. When I attempted to regress latent intercept and slope of the trajectory on an observed binary variable, however, the model failed to converge for boys (it was fine for girls). It will converge if I fix the loadings for the dependent variables. Is that an appropriate solution given the non-linearity of the trajectory? Any other thoughts?