I want to confirm if I am entering my variables in the proper way in SPSS for multiple regression. I have four variables: 1) student gender (dummy); 2) student gender proportionality (continuous); 3) faculty gender (dummy); and 4) student gender proportionality SQUARED (continuous).

I am interested in investigating the main effects and the interactions between the variables. My understanding from my old stats classes and an extensive online search is that when doing hierarchical regression you first enter the control variables, then the predictor variables, then the interaction terms. However, what do you do when you have two AND three way interactions AND some of the interactions contain a quadratic term?

Below is my strategy to enter the variables into SPSS but I’m not certain. I’ve also looked at several academic journal articles but NONE of the articles that I’ve found have the quadratic term as part of an interaction (perhaps that’s a clue to something I may be misunderstanding?). Further, this situation is not referenced in any of my stats books or articles.

Strategy for entering variables into SPSS:

- First level: control variables
- Second level: main effects (e.g., student gender, student gender proportionality and faculty gender)
- Third level: interactions between second level main effects plus quadratic term by itself? (student gender X student gender proportionality; student gender X faculty gender; student gender proportionality X faculty gender; student gender proportionality SQUARED)
- Fourth level: three way interaction and two way interactions with quadratic term? (student gender X student gender proportionality X faculty gender; student gender X student gender proportionality SQUARED; faculty gender X student gender proportionality SQUARED)
- Fifth level: three way interaction with quadratic term (student gender X faculty gender X student gender proportionality SQUARED)