One way could be to take the difference between the mean at the last time point and the mean at the first time point divided by the standard deviation at the first time point. You can find these values in the RESIDUAL output. You may want to post this question on a general discussion forum like SEMNET for other suggestions.
Hi Dr. Muthen, Thank you so much for your reply. I have tried to follow your instructions; however, I dont see standard deviation of timpeoint 1 in my RESIDUAL output. Am I missing something or do I need to calculate the SD? If so, please advise about how to do that.