Dear All,
I am implementing a four-way interaction for dummy variables.
I do have four dummies: j, k, l, m. Each of them assumes values 0 or 1.
To build up the term j*k*l*m I insert four first order terms (j, k, l, m), 6 two way interaction terms (j*k, j*l, j*m, k*l, k*m, l*m) and 4 three way interaction terms (j*k*l, j*k*m, j*l*m, k*l*m).
The content of variables k, l, m only makes sense if variable j takes value 1. In other words, the cases included in variables k, l, m are subcases of j=1.
The problem is the following: let's take, for instance, the three way term k*l*m. It measures whether the impact of k*l on the dependent variable changes in the level of m when j is 0. But, when j is 0, the content of variables k, l, m makes no more sense, since the content of variables k, l, m does have reason to exist only when variable j takes value 1.
So, how to deal with this issue? How to interpret terms like k*l, k*m, l*m, k*l*m, i.e. all those cases in which it is assumed that j takes value 0?
Thank you so much!
I am implementing a four-way interaction for dummy variables.
I do have four dummies: j, k, l, m. Each of them assumes values 0 or 1.
To build up the term j*k*l*m I insert four first order terms (j, k, l, m), 6 two way interaction terms (j*k, j*l, j*m, k*l, k*m, l*m) and 4 three way interaction terms (j*k*l, j*k*m, j*l*m, k*l*m).
The content of variables k, l, m only makes sense if variable j takes value 1. In other words, the cases included in variables k, l, m are subcases of j=1.
The problem is the following: let's take, for instance, the three way term k*l*m. It measures whether the impact of k*l on the dependent variable changes in the level of m when j is 0. But, when j is 0, the content of variables k, l, m makes no more sense, since the content of variables k, l, m does have reason to exist only when variable j takes value 1.
So, how to deal with this issue? How to interpret terms like k*l, k*m, l*m, k*l*m, i.e. all those cases in which it is assumed that j takes value 0?
Thank you so much!