# Specify latent true scores 
lx1 =~ 1 * x1 
lx2 =~ 1 * x2 
lx3 =~ 1 * x3 

# Specify mean of latent true scores 
lx1 ~ gamma_lx1 * 1 
lx2 ~ 0 * 1 
lx3 ~ 0 * 1 
# Specify variance of latent true scores 
lx1 ~~ sigma2_lx1 * lx1 
lx2 ~~ 0 * lx2 
lx3 ~~ 0 * lx3 
# Specify intercept of obseved scores 
x1 ~ 0 * 1 
x2 ~ 0 * 1 
x3 ~ 0 * 1 
# Specify variance of observed scores 
x1 ~~ sigma2_ux * x1 
x2 ~~ sigma2_ux * x2 
x3 ~~ sigma2_ux * x3 
# Specify autoregressions of latent variables 
lx2 ~ 1 * lx1 
lx3 ~ 1 * lx2 
# Specify latent change scores 
dx2 =~ 1 * lx2  
dx3 =~ 1 * lx3  
# Specify latent change scores means  
dx2 ~ 0 * 1  
dx3 ~ 0 * 1  
# Specify latent change scores variances  
dx2 ~~ 0 * dx2  
dx3 ~~ 0 * dx3  
# Specify constant change factor  
g2 =~ 1 * dx2 + 1 * dx3  
# Specify constant change factor mean  
g2 ~ alpha_g2 * 1  
# Specify constant change factor variance  
g2 ~~ sigma2_g2 * g2  
# Specify constant change factor covariance with the initial true score  
g2 ~~ sigma_g2lx1 * lx1 
# Specify proportional change component  
dx2 ~ beta_x * lx1  
dx3 ~ beta_x * lx2  
# Specify autoregression of change score  
dx3 ~ phi_x * dx2