Do you know if there is a way of dummy coding the interactions among three independent categorical variables using SPSS? (with two levels each)
$\begingroup$
$\endgroup$
Add a comment
|
1 Answer
$\begingroup$
$\endgroup$
You do not need dummy coding here. An interaction is the product between variables (see here for example). Since all of your variables are binary (0 or 1), the product will also be binary. Consider the following example of a three-way interaction between three binary variables V1, V2 and V3:
V1 V2 V3 IA-3 (V1*V2*V3)
0 0 0 0
0 0 1 0
0 1 0 0
0 1 1 0
1 0 0 0
1 0 1 0
1 1 0 0
1 1 1 1
As you can see, the three-way interaction IA-3 is binary, hence you do not need dummy coding here. So all you need is to calculate products. For the example above it would be
COMPUTE IA_3=V1 * V2 * V3.
EXECUTE.