Dear all, I am using the plm package for both fixed and random effects models on my country-year panel data. However, for some of the random effects models I get the following error:
Error in solve.default(OM) : system is computationally singular: reciprocal condition number = 1.78233e-18 The same models work fine for fixed effects. I have also noticed that once I remove some of my variables (mainly the Year variable) from the models, the regression can be completed. Does anyone know what the reason for this error might be? Any commenst will be highly appreciated and please accept my apologies if my question is too basic. Kind regards, Stanislav [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.