Dear all,

I am currently conducting a panel regression in Stata with the following variables:
CompanyID
Group (either 1 or 0)
Year (2005-2015)
Performance (profit in €)

When conducting a panel regression with random effects everything is fine. When conducting a fixed effects model I am receiving the following error message:
Variable "Group" omitted because of collinearity

Do you have an idea what could be the problem?

Best
OLMABA