topic Interaction term in Cox PH model in Statistical Procedures

Interaction term in Cox PH model

CHELS — Fri, 27 Aug 2021 14:11:23 GMT

Hello experts,

I have one question regarding interaction term. Let's say I have two dichotomous variables A and B. What is the difference between using an interaction term A*B in the model vs. creating a grouping variable that has four levels (A+B+; A+B-; A-B+; A-B-)?

Thanks!

Re: Interaction term in Cox PH model

data_null__ — Fri, 27 Aug 2021 14:19:45 GMT

Test it.

Re: Interaction term in Cox PH model

Ksharp — Fri, 27 Aug 2021 14:27:30 GMT

No difference .Both have the same design matrix.

Maybe @StatDave @SteveDenham @lvm @Rick_SAS know something .