The default estimation methods that are used in the Structural Equation Models platform depend on the presence or absence of missing data. The Structural Equation Models platform uses maximum likelihood (ML) estimation by default when there are no missing data. If any missing data are detected, then the platform uses full information maximum likelihood (FIML) estimation by default. In both cases, standard errors are obtained using the observed information matrix. The platform uses a combination of optimization algorithms in the estimation process, including Newton-Raphson, Quasi-Newton, and Fisher scoring.
Note: The ML method in the Structural Equation Models platform uses the sample size N in estimation, rather than N - 1.