Asthma control as measured by the ACQ5.

For group i = 1,2,…,n and item j = 1,…,5, each item acqj has a loading (λ_ij), an intercept (α_ij) and an error term (ε_ij). Each group has its own latent factor with mean (μ_i) and variance (σ²_i). *Partial measurement invariance may hold when constraints imposed on the intercepts (α_ij) are relaxed for one or more items in any subgroup.