Dear everyone, I try to regress a dynamic panel model with pgmm function in the plm package, but it doesn't work. The error report is "Error in names(coefficients) <- c(namesX, namest) : 'names' attribute [13] must be the same length as the vector [5]". My command is: reg.gmm<-pgmm(dynformula(ln_per_co2ec~ln_per_realgdp+ln_per_realgdp2,lag.form=list(1,0,0), log.form=FALSE),data=co2new,effect="individual",model="twosteps", gmm.inst=~ln_per_co2ec,lag.gmm=list(c(99,2)),transformation="d") Could you guys give me some hints on this problem? Thank you in advance. Best regards Limin [[alternative HTML version deleted]]