How to Use the Path Construction Tool

The Path Construction Tool is used to construct path model files in the PATH1 language, with virtually no typing. Because you type latent variable names only once, never have to type manifest variable names, and never have to enter paths manually, there is virtually no chance of a syntax error. Even extremely complicated models can be entered in a few minutes with this tool. For a detailed description of the various options on this dialog, refer to the Path Construction Tool topic.  

Setting Up - Editing the Latent Variables List. When the Path Construction Tool is first activated, the Latent Variables list will be presented in the From variables column. The variable names listed will be those already in the *.cmd file. If this is a new *.cmd file, or if you want to add latent variable names, you will have to edit the latent variable names list. To do this click the Edit Latent button to display the Edit Latent Variable Names dialog box.

Creating Paths - Adding Arrows and Wires. There are two basic types of paths, the arrow and the wire. Basic operation is as follows:

a. Choose a type of path by checking either the X-->Y or X--Y option in the Path Type group.

b. Select the type of variable in the From column of the Variables group.

c. Highlight the variable(s) from which to draw paths.

d. Select type of variable in the To column of the Variables group.

e. Highlight the variables to which paths will be drawn.

f. Click the Add>> button.

At this point, the requested paths will appear in the Paths box on the far right side of the screen.  

Creating Paths - Multiple Path Commands. Besides the basic arrow and wire path types, the Path Type group includes options for three additional multiple path commands. These commands automate operations which are (a) highly repetitive, and (b) common to most path diagrams. They are described below.

Residual. This option creates residual (or "disturbance") variables automatically for all currently highlighted variables in the To column. Suppose, for example, you want to create residuals ("unique factors") for all the manifest variables (X1, X2, X3, X4, X5, X6) in the Child.sta file. You would simply a) select Manifest in the To variables column; b) highlight all the variables; c) select Residual as the Path Type option; d) enter a Base Name (say, EPS) and a Base Number (say, 1) in the Residual Vars group; e) click the Add>> button. At this point, paths for residual variables EPS1, EPS2, EPS3, EPS4, EPS5, and EPS6 and their variances will be added automatically, and these residual variable names will be added to the latent variables list.

Correlations. Frequently in a structural model, you need to insert paths for the correlation coefficients among a set of latent or manifest variables. STATISTICA does this automatically for all variables highlighted in the To column. For example, if you highlight variables X1, X2, X3 and click the Correl. button, you get the following paths:

[X2]-1-[X1]

[X3]-2-[X1]

[X3]-3-[X2]

[X1]-{1.0}-[X1]

[X2]-{1.0}-[X2]

[X3]-{1.0}-[X3]

Covariances. This option creates paths for all the variances and covariances for all variables highlighted in the To variables column. It operates in virtually the same way as the Correl. option.

Adding Paths via the Add>> button. The Add>> button causes paths to be created, according to the currently created options.  The new paths will appear immediately in the Paths box. If you don't like them, simply delete them with the Cut command (see below).

Editing the Paths Already Created. The program offers editing capabilities, to change and/or reorganize the paths already created. These paths are listed in the Paths list box on the right side of the screen. Available functions include Cut, Paste, and Copy.

Removing All Paths involving a Latent Variable. The program offers an especially easy way to completely eliminate a latent variable from an analysis. Simply activate the Edit Latent Variables Names dialog box, and delete the name of the latent variable that you want to remove from the model. After you click OK, all paths involving this variable, and the variable itself, will be deleted from the model.

The Parameters Group - Controlling the Parameter Numbers of Paths. The Parameters group contains functions that enable you to control if, and how, free parameter numbers are inserted in the paths you create.

The Start Value Group - Controlling Start Values. The fields in the Start Value group control whether a start value is added to a path, and what value is added.

Adding Comments to the Model File. You can add comments to the analysis syntax by clicking the Comment button.

Adding Group and Endgroup Commands. You can add Group and Endgroup commands by clicking the appropriate buttons.

Adjusting Analysis Parameters. You can display the Analysis Parameters dialog box by clicking the Parameters button.