Building a Model

Requirements for Building a Model

Single Effects

Create a Main Effect

Create Crossed Effects (Interactions)

Create a Polynomial Degree Effect

Create a Nested Effect

Standard Models

Create a Two-Way Factorial

Create a Full Factorial

Create an N-Way Factorial

Create Polynomial Effects of the Nth Order

Requirements for Building a Model

By default, no effects are specified, which results in the task fitting an intercept-only model. Here is what you see on the Model tab.

Model Tab with Only the Intercept as an Effect

To specify a model effect, you must assign at least one variable to the Classification variables role or the Continuous variables role. On the Model tab, click Edit Icon

to open the Model Effects Builder.

When you close the Model Effects Builder, any effects that you created appear on the Model tab.

Model Tab with Intercept and Team as an Effect

Single Effects

Create a Main Effect

Select the variable name in the Variables box.
Click Add to add the variable to the list of model effects.

Create Crossed Effects (Interactions)

Select two or more variables in the Variables box. To select more than one variable, press Ctrl.
Click Cross.

Create a Polynomial Degree Effect

Select one or more continuous variables in the Variables box.
In the list of single effects, click Polynomial Degree=N.
Specify higher-degree crossings by adjusting the number in the N field.

For example, if you select Age, click Polynomial Degree=N, and specify 3 as the value of N, the Age*Age*Age effect is created.

Create a Nested Effect

Nested effects are specified by following a main effect or crossed effect with a classification variable or list of classification variables enclosed in parentheses. Here are examples of nested effects: B(A), C(B*A), D*E(C*B*A). In this example, B(A) is read "B within A."

Select the classification variable in the Model Effects Builder.
Click Nest. The Nested window appears.
Select the variable to use in the nested effect. Click Outer or Nested within Outer to specify how to create the nested effect.

Note: The Nested within Outer button is available only when a classification variable is selected.
Select the effect that you want to nest.
Click Add.

Standard Models

Create a Two-Way Factorial

Select two or more variables in the Variables box.
Click Two-Way Factorial.

For example, if you select the Age and Height variables and then click Two-Way Factorial, the Age*Height effect is created.

Create a Full Factorial

Select two or more variables in the Variables box.
Click Full Factorial.

For example, if you select the Height, Weight, and Age variables and then click Full Factorial, these model effects are created: Age, Height, Weight, Age*Height, Age*Weight, Height*Weight, and Age*Height*Weight.

Create an N-Way Factorial

Select two or more variables in the Variables box.
Click N-way Factorial and specify the value of N.

For example, if you select the Height, Weight, and Age variables, click N-way Factorial, and then specify the value of N as 2, these model effects are created: Age, Height, Weight, Age*Height, Age*Weight, and Height*Weight. If N is set to a value greater than the number of variables in the model, N is effectively set to the number of variables.

Create Polynomial Effects of the Nth Order

Select one or more continuous variables in the Variables box.
In the list of standard models, click Polynomial Order=N.
Specify higher-degree crossings by adjusting the number in the N field.

For example, if you select the Age and Height variables, click Polynomial Order=N, and specify 3 as the value of N, these model effects are created: Age, Age*Age, Age*Age*Age, Height, Height*Height, and Height*Height*Height.