Dear R users What would be the best way to approach estimating a panel regression with twoways random effects, on unbalanced data? Unfortunately, the "plm" package has no implementation of twoways random effects for unbalanced data. Currently I'm considering two approaches: - extend "plm" to cover this type of panel regression. (For the authors, cc'ed:) Would implementing this be particularly difficult? Where should one look in the source? - perform the regressions manually as suggested in “Econometrics in R” [1]. But what would be the correct lme() syntax for a twoways RE model? For example, library("AER") library("plm") data("Grunfeld", package = "AER") pgr <- plm.data(Grunfeld, index = c("firm", "year")) gr_re <- plm(invest ~ value + capital, data = pgr, model = "random", effect="individual") gr_lme <- lme(invest ~ value + capital, Grunfeld, random=~1|firm) summary(gr_re) summary(gr_lme)
For this "individual" RE model, both plm() and lme() yield apparently similar results. While for the "twoways" one not quite: gr_re <- plm(invest ~ value + capital, data = pgr, model = "random", effect="twoways", random.method = "amemiya") gr_lme <- lme(invest ~ value + capital, Grunfeld, random=~1|firm/year) summary(gr_re) summary(gr_lme) Would this be the correct lme() syntax for a "twoways" panel model? Would it work for unbalanced data? Any ideas would be great. Thank you Liviu [1] http://cran.r-project.org/doc/contrib/Farnsworth-EconometricsInR.pdf -- Do you know how to read? http://www.alienetworks.com/srtest.cfm http://goodies.xfce.org/projects/applications/xfce4-dict#speed-reader Do you know how to write? http://garbl.home.comcast.net/~garbl/stylemanual/e.htm#e-mail ______________________________________________ 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.