I am using the Levin Lin Chiu test in Stata 17 to test for stationarity in a panel of 115 countries, from 1995 to 2015 with a delta of five years. This means N(115) * T(5)= 575 obs.


. xtunitroot llc Trade_to_GDP
no observations
r(2000);


I did the summary and describe of the variables and all are numeric. Also, the panel is strongly balanced. So I don´t understand why it says no obs.

Any help is appreciated, thank you!