Hello,

I am working with PISA 2012 dataset and I am comparing Eastern and Western European countries. Therefore, I would need to use country fixed effects. I am confused as to how to proceed with that with the pisareg command. I have created dummies for each country, but when I run the regression I get this as the error when I am trying to extract the results

"matrix e(b) not found; run/post a regression, or specify varlist for non-regression outputs"

Can someone help me on how to proceed with this problem?

Thank you very much!