A1348
Title: The structural-after-measurement (SAM) approach to SEM
Authors: Yves Rosseel - Ghent University (Belgium) [presenting]
Abstract: In structural equation modeling (SEM), the measurement and structural parts of the model are usually estimated simultaneously. However, since the birth of SEM in the '70s, various authors have advocated that the measurement part should be first estimated, and then the structural part. It is called the structural-after-measurement (SAM) approach. The purpose is to describe the so-called 'local' SAM method, where the mean vector and variance-covariance matrix of the latent variables are expressed as a function of the observed summary statistics and the parameters of the measurement model. The method includes two-step corrected standard errors and local fit measures. Several recent developments are then briefly discussed that are based on the SAM approach, including the inclusion of latent quadratic and interaction terms, the use of non-iterative estimators for the measurement part of the model, small-sample corrections, and various approaches to studying measurement invariance in the setting where the number of groups is very large. Finally, a software implementation of the SAM approach that is available in the R package lavaan is discussed.
