Dear Limin, might be just about anything. Could you please provide a reproducible example? Best, Giovanni ----------------- Original message ---------------------- Message: 51 Date: Mon, 17 May 2010 10:36:03 +0800 (CST) From: ??? <dlmsos at 163.com> To: r-help at r-project.org Subject: [R] pgmm function Message-ID: <b2cba0.35fc.128a41e3684.Coremail.dlmsos at 163.com> Content-Type: text/plain 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 -------------------------------------------------------- Giovanni Millo Research Dept., Assicurazioni Generali SpA Via Machiavelli 4, 34132 Trieste (Italy) tel. +39 040 671184 fax +39 040 671160 Ai sensi del D.Lgs. 196/2003 si precisa che le informazi...{{dropped:13}}