Hi all,

I have a panel data on bilateral trade volume of 55 country pairs for 15 years time period (so an unbalanced 15*55*15 matrix).
So far, I am done with reshaping and trying to declare the panel data before running the regression.

when I ran the following command:

egen group = group(countryi countryj)
su group, meanonly
xtset group year

the result revealed
xtset group year
repeated time values within panel
r(451);

In an attempt to fix it, I did

code
drop if year==year[_n-1]
xtset group year, yearly

and I got the panel with weak balanced. Then I ran the regression and got the r2000, no observation.

I could not figured out how best can I fix it. Any help or guidance would be much appreciated.
I am happy to provide with more details if needed.

Cheers,
Thanh Hao