[R] theta parameter - plm package

[alfonso.carfora at uniparthenope.it]

Hi all,

what indicates the parameter theta in the summary of a random effect  
panel model estimated with the plm function?

example:

data("Produc", package = "plm")
zz <- plm(log(gsp) ~ log(pcap) + log(pc) + log(emp) + unemp,  
model="random", data = Produc, index = c("state","year"))

summary(zz)

Effects:
                    var  std.dev share
idiosyncratic 0.001454 0.038137 0.175
individual    0.006838 0.082691 0.825

theta:  0.8888

Thanks
Alfonso