We have deliberately delayed presenting the matrix notation used in calculating structural equation models because we wanted to rst present the basic concepts, principles, and applications of SEM. SEM models are typically analyzed using the eight different matrices illustrated in Figure 17.1 (Hayduk, 1987); although a few new ones have emerged, for example, tau and kappa. SEM models may use some combination of these matrices, but not use all of the matrices in a given analysis, for example, path analysis or conrmatory factor analysis.