Hi everyone,
I have to use the command felsdvregdm to disentagle fixed effects. Unfortunately, I'm not understanding how it works. Running code the error it gives me is the following:


The refference collection variable (called event) is not exclusive to groups
Sum-to-zero effects cannot be calculated if reference collections are in multiple groups
Redefine refference collection, so that each value of the reff is unique to a group
perhaps using egen group() command
r(197);

I don't understand what this group is about. Can you help me?

Thank you very much