Build Terms and Custom Terms

Build terms
Use this choice when you want to include non-nested terms of a certain type (such as main effects) for all combinations of a selected set of factors and covariates.
  1. Select one or more factors or covariates or a combination of factors and covariates.
  2. Select a method for building the terms and click Add.
    Interaction
    Creates the highest-level interaction term of all selected variables. This is the default.
    Main effects
    Creates a main-effects term for each variable selected.
    All 2-way
    Creates all possible two-way interactions of the selected variables.
    All 3-way
    Creates all possible three-way interactions of the selected variables.
    All 4-way
    Creates all possible four-way interactions of the selected variables.
    All 5-way
    Creates all possible five-way interactions of the selected variables.
  3. Repeat the process until you have all of the terms that you want in the model.
Build custom terms
Use this choice when you want to include nested terms or when you want to explicitly build any term variable by variable. Building a nested term involves the following steps:
  1. Select a factor or covariate that is nested within another factor and click the move button.
  2. Click Within.
  3. Select the factor within which the previous factor or covariate is nested and click the move button.
  4. Click Add.
  5. Optionally, you can include interaction effects by using By, or you can add multiple levels of nesting to the nested term.