GLM Effects for Within Design

Select the Custom within design button in the Specify Within-Subjects Factors dialog box to display the GLM Effects for Within Design dialog box. Use these options to specify the effects for the within-subject (repeated measures) design. Repeated measures factors can be specified via the Specify Within-Subjects Factors dialog box. Repeated measures designs are discussed in the Within-subject (repeated measures) design topic of the Introductory Overview.

Element Name Description
Use default full-factorial design for the within-subject factors If you select the Use default full-factorial design for the within-subject factors option button, the options in the Within factors, Method, and Effects in within design group boxes are not available. In that case, the default full factorial design is created for the repeated measures factors.
Use custom effects for the within-subject factors Select the Use custom effects for the within-subject factors option button to select the specific effects for the selected factors that are to be included in the model. Note that, unlike in the between-group design, the exclusion of some within subject effects from the full factorial within subject design does not change the result for those effects left in the model; thus, this option is mostly useful when you want to produce less cluttered results spreadsheets for complex within-subject designs involving many factors. See the Introductory Overview for details concerning the computations involved in within-subject (repeated measures) designs.
OK Click the OK button after you have specified the effects to return to the GLM Quick Specs Dialog - Quick tab (or the GLM Analysis Wizard Extended Options - Quick tab).
Cancel Click the Cancel button to return to the GLM Quick Specs Dialog - Quick tab (or the GLM Analysis Wizard Extended Options - Quick tab); any changes made are disregarded.
Within factors The Within factors group box (and the Method and Effects in within design group boxes) allow you to specify effects for the within-subject design in the following manner:

Select the within-subject (repeated measures) factors in the Within factors group box by clicking on them; select multiple factors by holding down the CTRL key while clicking on the respective factors; select a list of consecutive factors by dragging the mouse over the list.

Choose the design for those factors by clicking on the respective button in the Method group box.

The generated effects will automatically be listed in the Effects in within design group box. You can further edit the effects in the Effects in within design group box by using the Remove or Clear all buttons; you can also reorder the effects in the Effects in within design group box (see below).

Method The Method group box contains the available options for including the selected factors as effects in the (custom) design. Some options may only be available if the appropriate number of factors were chosen in the Within factors group box. See also the description of the GLM syntax, in particular of the WDESIGN keyword for details on how to specify within-subject (repeated measures) designs in GLM.
Add Click the Add button to add the main effects for the chosen factors to the Effects in within design group box.
Cross Click the Cross button to create the respective interaction term for all selected factors (e.g., R1*R2*R3). Note that this button is only available if two or more factors are selected;
Full factorial Click the Full factorial button to construct a full factorial design -- up to the degree specified in the Degree field -- for the selected factors (e.g., R1 R2 R3 R1*R2 R1*R3 R2*R3 R1*R2*R3). Note that this button is only available if two or more factors are selected.
Fact. to deg Click the Fact. to deg. (Factorial to degree) button to construct a factorial design -- up to the degree specified in the Degree field -- for the selected factors (e.g., R1 R2 R3 R1*R2 R1*R3 R2*R3). Note that this button is only available if two or more factors are selected.
Degree Use the Degree field in conjunction with the Full factorial and Fact. to deg. options; see above.
Effects in within design The Effects in within design group box displays the effects currently in the design. These effects can further be edited via the following options:
Remove Click the Remove button to remove the selected effects from the Effects in within design group box.
Clear all Click the Clear all button to remove (clear) all effects from the Effects in within design group box.
Reordering effects To reorder the effects in the Effects in within design group box, first select them (e.g., click on the effect or list of effects), then move the mouse cursor to the desired location in the list, and when the mouse cursor changes to the insertion bar , click the mouse button to move the selected effects.