IBM® SPSS® Amos™ 28

In order to decide whether a parameter is identified, or whether an entire model is identified, Amos examines the rank of the matrix of approximate second derivatives, and of some related matrices. The method used is similar to that of McDonald and Krane (1977). There are objections to this approach in principle (Bentler & Weeks, 1980; McDonald, 1982). There are also practical problems in determining the rank of a matrix in borderline cases. Because of these difficulties, you should judge the identifiability of a model on a priori grounds if you can. With complex models, this may be impossible, so that you will have to rely on Amos's numerical determination. Fortunately, Amos is pretty good at assessing identifiability in practice.