The CALIS Procedure

 
Classes of Statements in PROC CALIS

To better understand the syntax of PROC CALIS, it is useful to classify the statements into classes. These classes of statements are described in the following sections.

PROC CALIS Statement

is the main statement that invokes the CALIS procedure. You can specify options for input and output data sets, printing, statistical analysis, and computations in this statement. The options specified in the PROC CALIS statement will propagate to all groups and models, but are superseded by the options specified in the individual GROUP or MODEL statements.

GROUP Statement

signifies the beginning of a group specification. A group in the CALIS procedure is an independent sample of observations. You can specify options for input and output data sets, printing, and statistical computations in this statement. Some of these group options in the GROUP statement can also be specified in the MODEL or PROC CALIS statement, but the options specified in the GROUP statement supersede those specified in the MODEL or PROC CALIS statement for the group designated in the GROUP statement. For group options that are available in both of the GROUP and PROC CALIS statements, see the section Options Available in the GROUP and PROC CALIS Statements. For group options that are available in the GROUP, MODEL, and PROC CALIS statements, see the section Options Available in GROUP, MODEL, and PROC CALIS Statements. If no GROUP statement is used, a single-group analysis is assumed. The group options for a single-group analysis are specified in the PROC CALIS statement.

The GROUP statement can be followed by subsidiary group specification statements, which specify further data processing procedures for the group designated in the GROUP statement.

Subsidiary Group Specification Statements

are for specifying additional data processing attributes for the input data. These statements are summarized in the following table:

Statement

Description

FREQ

Specifies the frequency variable for the input observations

PARTIAL

Specifies the partial variables

VAR

Specifies the set of variables in analysis

WEIGHT

Specifies the weight variable for the input observations

These statements can be used after the PROC CALIS statement or each GROUP statement. Again, the specifications within the scope of the GROUP statement supersede those specified after the PROC CALIS statement for the group designated in the GROUP statement.

MODEL Statement

signifies the beginning of a model specification. In the MODEL statement, you can specify the fitted groups, input and output data sets for model specification or estimates, printing options, statistical analysis, and computational options. Some of the options in the MODEL statement can also be specified in the PROC CALIS statement. These options are called model options. Model options specified in the MODEL statement supersede those specified in the PROC CALIS statement. For model options that are available in both of the MODEL and PROC CALIS statements, see the section Options Available in the MODEL and PROC CALIS Statements. If no MODEL statement is used, a single model is assumed and the model options are specified in the PROC CALIS statement.

Some of the options in the MODEL statement can also be specified in the GROUP statement. These options are called group options. The group options in the MODEL statement are transferred to the groups being fitted, but they are superseded by the group options specified in the associated GROUP statement. For group options that are available in the GROUP and the MODEL statements, see the section Options Available in GROUP, MODEL, and PROC CALIS Statements.

The MODEL statement itself does not define the model being fitted to the data; the main and subsidiary model specification statements that follow immediately after the MODEL statement do. These statements are described in the next two sections.

Main Model Specification Statements

are for specifying the type of the modeling language and the main features of the model. These statements are summarized in the following table:

Statement

Description

COSAN

Specifies general mean and covariance structures in matrix terms

FACTOR

Specifies confirmatory or exploratory factor models

LINEQS

Specifies models by using linear equations

LISMOD

Specifies models in terms of LISREL-like model matrices

MSTRUCT

Specifies parameters directly in the mean and covariance matrices

PATH

Specifies models by using the causal paths of variables

RAM

Specifies models by using RAM-like lists of parameters

REFMODEL

Specifies a base model from which the target model is modified

You can use one of these statements for specifying one model. Each statement in the list represents a particular type of modeling language. After the main model specification statement, you might need to add subsidiary model specification statements, as described in the following section, to complete the model specification.


Subsidiary Model Specification Statements

are used to supplement the model specification. They are specific to the types of the modeling languages invoked by the main model specification statements, as shown in the following table:

Statement

Specification

Modeling Languages

COV

Covariance parameters

FACTOR, LINEQS

MATRIX

Parameters in matrices

COSAN, LISMOD, MSTRUCT

MEAN

Mean or intercept parameters

FACTOR, LINEQS, PATH

PCOV

(Partial) covariance parameters

PATH

PVAR

(Partial) variance parameters

FACTOR, PATH

RENAMEPARM

New parameters by renaming

REFMODEL

VARIANCE

Variance parameters

LINEQS

Notice that the RAM modeling language does not have any subsidiary model specification statements, because all model specification can be done in the RAM statement.

Model Analysis Statements

are used to request specific statistical analysis, as shown in the following table:

Statement

Analysis

DETERM

Sets variable groups for computing the determination coefficients; same as the STRUCTEQ statement

EFFPART

Displays and partitions the effects in the model

FITINDEX

Controls the fit summary output

LMTESTS

Defines the Lagrange multiplier test regions

SIMTESTS

Defines simultaneous parametric function tests

STRUCTEQ

Sets variable groups for computing the determination coefficients; same as the DETERM statement

TESTFUNC

Tests individual parametric functions

Notice that the DETERM and the STRUCTEQ statements function exactly the same way.

Optimization Statements

are used to define additional parameters and parameter constraints, to fine-tune the optimization techniques, or to set the printing options in optimization, as shown in the following table:

Statement

Description

BOUNDS

Defines the bounds of parameters

LINCON

Defines the linear constraints of parameters

NLINCON

Defines the nonlinear constraints of parameters

NLOPTIONS

Sets the optimization techniques and printing options


Other Statements

that are not listed in preceding sections are summarized in the following table:

Statement

Description

BY

Fits a model to different groups separately

OUTFILES

Controls multiple output data sets

PARAMETERS

Defines additional parameters or superparameters

SAS programming statements

Define parameters or functions

Note that SAS programming statements include the ARRAY statement and the mathematical statements for defining parameter interdependence.