Hi I am working on a panel data, my data are clustered/grouped by the variable "yearctry", I am running the regression below, but I cant make the regression recognise "yearctry" as the panel variable in the regression myProbit<- glm(s ~ age + gender + gemedu + gemhinc + es_gdppc + imf_pop + estbbo_m, family = binomial(link = "probit"), data adpopdata) Can anyone help me do this please??? Thanks Saurav -- Dr.Saurav Pathak PhD, Univ.of.Florida Mechanical Engineering Doctoral Student Innovation and Entrepreneurship Imperial College Business School s.pathak08@imperial.ac.uk 0044-7795321121 [[alternative HTML version deleted]]