Hello everybody!

I am quite new to Stata, and have much to learn. However, I am trying to perform a regression on a data set with data taken from CEPII. I have a panel data with many countries and their trade partner as observation, and the variables I have included are exports, imports, distance, population, GDP, colonial history, common languages, contiguity and the existence of free trade agreement.

However, when trying to perform the command xtreg logXPTOT lgdp_o lgdp_d lpop_o lpop_d logDist Comlang Contig Evercol EU Zaf_fta, fe, I get the error message: ""variable ccode not found". I have installed xtpattern. Another question, how do I generate the variable fe?

I would be very grateful if someone had a solution to my problem.

Thank you