Structural equation models allow for estimation of complex networks including latent and observed variables, and endogenous and exogenous factors. When an SEM is fit, the model results are summarized in terms of a number of fit indices. I assume these indices (and their $p$-values) are variations of goodness-of-fit-tests. An overview is given by Kenny here.
- What measures is an SEM capable of generating predicted values for?
- The site refers to a $\chi^2$ value but does not explain how it is generated. When there is no clear, single "Y" in the model, is every single variable in the model taken as an (expected-observed)?
- How is it possible for an SEM to have a low R^2 but "perfect fit"? And what does perfect fit mean in this sense?