Model Specification

PROC TCALIS provides several modeling languages to specify a model. Different modeling languages in PROC TCALIS are signified by the main model specification statement used. In the TCALIS procedure, FACTOR, LINEQS, LISMOD, MSTRUCT, PATH, and RAM are the main modeling specification statements. Each of these statements invokes a specific modeling language. Depending on your modeling philosophy and the type of the model, you can choose a modeling language that is most suitable for your application. Models specified using structural equations can be transcribed directly into the LINEQS statement. Models that are hypothesized using path diagrams can be described easily in the PATH or RAM statement. First-order confirmatory or exploratory factor models are most conveniently specified using the FACTOR and MATRIX statements. Traditional LISREL models are supported through the LISMOD and MATRIX statements. Finally, patterned covariance and mean models can be specified directly by the MSTRUCT and MATRIX statements.

For most applications, the PATH and LINEQS statements are the easiest to use. In other cases, the FACTOR, LISMOD, MSTRUCT, or RAM statement might be more suitable. See the section Which Modeling Language? in Chapter 88, The TCALIS Procedure, for a more detailed discussion.

You can save a model specification in an OUTMODEL= data set, which can then be used with the INMODEL= option to specify the model in a subsequent analysis.