I am running a hierarchical regression model. (That is, I am running a series of regression models, adding additional variables each time so that each model is nested within the next. Here, each model is called a "block".) I have four ordinal Likert-style independent variables (named IV1, IV2, IV3, IV4, all centered) and one dependent variable (named DV).
However, I am interested only in selected hypotheses / relationships which are:
- H1: IV1 >>> DV
2-way interactions (moderations)
- H2: IV1 >>> DV moderated by IV2
- H3: IV1 >>> DV moderated by IV3
3-way interactions (moderated moderation)
- H4: IV1 >>> DV moderated moderation with IV2 * IV4
- H5: IV1 >>> DV moderated moderation with IV3 * IV4
I am conducting a hierarchical regression using SPSS.
- Block 1: only controls
- Block 2: direct effects (IV1, IV2, IV3, IV4)
- Block 3: 2-way interactions Block 4: 3-way interactions
- Regarding Block 2 and 3: do I need to include all possible 2-way / 3-way interactions or only the ones which I am hypothesizing?
- From which block do I read the results? For example, for the direct effects would I look only at block 2 or the "full model" from block 4?