Hello everybody,

I tried to use contrast in order to see if I should use some categorical variables after my regression. I have never used this command before so please let me know if my interpretation of the use of the command is wrong per se.

So I type my regression like:

xtreg yvar xvars i.year year#country year#industry, fe vce(cluster ID)
contrast year#country
contrast year#industry

and get an almost empty table apart from: year#country not testable and denominator = 2708.

What am I doing wrong?